Two for One: Nvidia's Dual-Chip GeForce 7950 GX2 Reviewed

The new graphics card from Nvidia, GeForce 7950 GX2, is to be the subject of this review. It is the first officially announced dual-GPU card from Nvidia which, unlike GeForce 7900 GX2, is meant for the retail market. Let’s see if it is now the best single graphics card in the world!

by Alexey Stepin , Anton Shilov
06/09/2006 | 06:01 PM

Graphics cards with more than one graphics-processing chip on board are nothing new, actually. They have been long used by professionals while in the consumer market products like Voodoo Graphics, Voodoo2 and Voodoo5 got some renown, too. In recent years some companies, mostly majors like ASUS Computer, Gigabyte Technology and Microstar International, have also submitted their exclusive solutions on two Nvidia GeForce chips to the public.

 

Developed by a single company, dual-chip cards from the mentioned manufacturers couldn’t get much popularity, although often were a very good buy. But there was no real urgency for dual-chip graphics cards in 2005 because Nvidia managed to turn out ever faster products on the same chip whereas ATI Technologies was trying to begin mass production of its Radeon X1000.

Early this year, however, ATI overtook Nvidia in terms of performance by releasing its new flagship Radeon X1900 XTX in mass quantities. Having 48 pixel processors on board, the new card left all the then-available solutions from Nvidia behind and remained unbeatable even by Nvidia’s new flagship GeForce 7900 GTX.

Many users are watching the struggle between ATI and Nvidia as if it were sports like racing or boxing and take close notice only of those graphics cards that get to be champions. Therefore both the companies are trying hard to get the yellow jersey of the leader. Realizing that its GeForce 7900 GTX wouldn’t come out of its fight with the Radeon X1900 XTX as an absolute winner, Nvidia deliberately put a low price of $499 on it. This could only mean that the company had a better solution to be placed at the price peak of $649 the company had climbed before.

At the beginning of June 2006, three months after the release of GeForce 7900, Nvidia introduced its highly anticipated GeForce 7950 GX2 that is supposed to become an all-around leader among single graphics cards. It’s either the frequency potential of GeForce 7900 is exhausted at 650-700MHz or in order to make four-processor (quad-SLI) systems more reliable but Nvidia didn’t increase the frequencies of the new flagship product, only put two GPUs on it which are sure to beat all the rivals and to give system integrators the opportunity to produce simpler quad-SLI computers.

GeForce 7950 GX2: Two in One

By releasing the GeForce 7950 GX2, Nvidia not only claims to be the manufacturer of the fastest graphics solution but also implies that its SLI technology can ensure a good performance boost within a single graphics card.

It’s no secret that you only need a mainboard with two PCI Express x16 slots to successfully use Nvidia SLI technology; the lack of driver support for SLI mode on non-nForce chipsets is largely due to commercial reasons. But when releasing its single card with two chips working in SLI mode, Nvidia had to ensure maximum compatibility with all modern platforms, i.e. make this SLI config compatible with as many existing chipsets as possible.

As we said above, it’s necessary to have two PCI Express x16 slots on the mainboard to turn on multi-GPU mode. To provide this, the chipset’s North Bridge must support PCI Express lanes reprogramming, i.e. their functioning as PCI Express x16 for a single card and as PCI Express x8 for two cards (when there are 16 PCI Express lanes in total). This feature is supported by a number of modern chipsets, though not by all. To maintain compatibility with the latter (and to support quad-SLI mode on its own platforms), Nvidia installs a special PCI Express x48 switch on its dual-chip graphics cards which is responsible for reallocation of the PCI Express x16 lanes.

Unfortunately, even the switch chip cannot make the Nvidia GeForce 7950 GX2 compatible with all the platforms available. A mainboard must explicitly support the new card in its BIOS – otherwise compatibility is not guaranteed. For example, we tried to install our sample of GeForce 7950 GX2 into our modified testbed with an Intel Desktop Board D925XCV to measure its power consumption, but the computer wouldn’t start up. After we installed the latest BIOS version, the mainboard did nothing more than spin up the fan of the graphics card – it didn’t even make it to the POST!

Nvidia tries to safeguard its users against such unpleasant surprises and has a dedicated web-page that lists all the mainboard models compatible with the 7950 GX2 graphics card. At the time of our writing this the list included 39 mainboards, 26 on Nvidia chipsets, 11 on Intel chipsets, 1 on an ATI chipset and 1 on a VIA chipset.

We expect this list to be getting longer since there are hundreds of PCI Express mainboards available, produced since June 2004. Not all users of platforms with powerful processors like Pentium Extreme Edition will be able to use the new card. But considering the high power requirements of the newest graphics cards, not all people can use a Radeon X1900 XTX, either (you shouldn’t have this problem if you’ve got a good-quality 450W PSU, though).

Specification and Alternatives

Here is the official specification of the new graphics card so that you could make out what to expect from it.

As you see, this is the first single graphics card to support 8x and 16xs full-screen antialiasing due to SLI AA technology. Up till now owners of single cards on Nvidia’s GeForce chips had only a very resource-consuming hybrid 8xs FSAA which very often resulted in a tremendous performance hit. But now you have a rather fast 8x multi-sampling as well as a high-quality 16xs antialiasing which should be fast enough in many not-very-new games. Thus, the GeForce 7950 GX2 is superior to GeForce 7900 GTX as well as to Radeon X1900 XTX when it comes to FSAA quality.

The GeForce 7950 GX2 is positioned against the Radeon X1900 XTX, but the new product can also be compared with a pair of GeForce 7900 GT or a hypothetic pair of Radeon X1900 GT cards. Yet you should realize that both CrossFire and SLI have limited compatibility with chipsets and cannot be directly compared with a single, even though not quite problem-free, GeForce 7950 GX2.

Note that although GeForce 7950 GX2 is actually one of the blocks for a quad SLI system, Nvidia does everything they can to prevent this technology from penetrating the DIY market and keep it a prerogative for system integrators exclusively. They claim that the physical implementation of quad SLI is too complicated, which is partially true. However, you can also read the corresponding reviews to see that Nvidia’s own drivers are still too raw for proper quad SLI support.

PCB Design

Similar to the GeForce 7900 GTX2, the GeForce 7950 GX2 graphics card is a two-storied device that consists of two PCBs placed one above another.

 

However, this card is more compact because it is shorter. It is comparable in size with Radeon X1900 XTX or GeForce 7900 GTX. Although the GeForce 7950 GX2 is still somewhat longer than the modern single-chip flagship solutions from ATI and Nvidia, it should fit perfectly into any standard system case of ATX form-factor. It may be troublesome to install this card into a small system case, but top-performance gaming stations this product is targeted at don’t generally come in small sizes.

 

The PCBs are connected into a single whole by means of four metal hexahedral posts. We unfastened the four screws and took the GeForce 7950 GX2 apart. We also dismantled both coolers for you to have a better view of the design of the new device from Nvidia:

As you see, the bottom PCB bears much more components than the top one because it is equipped with a PCI Express x16 slot and carries a PCI Express x48 switching chip besides one of the two G71 processors.

You can read the marking of both the chips in the snapshot. The GPU is an ordinary sample of G71 D-H-N revision A2 dated the 14th week of 2006. The bridge chip is marked as BR03, has A3 revision, and is dated the 13th week of the same year. According to Nvidia, the switch chip is only responsible for allocation of the PCI Express lanes between the two GPUs whereas synchronization of the GPUs is performed via MIO interface as in traditional Nvidia SLI configurations.

Also on this PCB there is a power circuit (not a very complex one due to the low power consumption of the G71 chip), a connector for the top card, and a MIO connector. The latter connects two GeForce 7950 GX2 cards to work as a quad-SLI subsystem, but it is unclear how this connector is used if the MIO interfaces of both the GPUs in a GeForce 7950 GX2 are already connected internally.

As far as we know, the GeForce 7800/7900 chips feature two MIO interfaces with the bandwidth of 1GB/s each. However, one of them is only enabled when we have a quad SLI system.

The top PCB of the GeForce 7950 GX2 looks emptier. The power circuit here is simpler than on the bottom PCB and includes fewer elements, although it is this PCB that receives external power (it carries a standard 6-pin PCI Express power connector for that). The difference may probably be due to the lack of necessity to power the PCI Express bridge chip.

Another difference from the GeForce 7900 GX2 is that the top PCB now carries a TV output and DVI-I connectors for monitors.

A curious fact, this graphics processor is dated the 13th week of the year and so belongs to another batch than the bottom one. This doesn’t matter much, of course, since the chips have the same revision and are absolutely identical. Both the GPUs of the GeForce 7950 GX2 card are clocked at 500MHz and this frequency is the same for all the subunits (pixel and vertex processors, ROPs and TMUs). So the GeForce 7950 GX2 doesn’t differ from the GeForce 7900 GX2 in this respect.

Considering that it’s impossible to mount a massive (i.e. efficient) cooler on this two-storied card, it’s reasonable to keep the GPU clock rate low, even though the G71 is not a very hot chip by itself. Nvidia puts its stake on the combined power of the two processors rather than on their frequency. We’ll see soon if Nvidia’s right here.

According to Nvidia, the peak power consumption of the GeForce 7950 GX2 is 143W, but this number looks a bit exaggerated. As we know, the standard GeForce 7900 GT consumes about 48W under load. The GeForce 7950 GX2’s GPUs work at a 50MHz higher frequency, but its memory frequency is lower compared with the GeForce 7900 GT’s (600MHz against 660MHz). The new card has more memory chips, so we suppose it consumes about 110-120W under load, comparable with the consumption of the power-hungry ATI Radeon X1900 XTX.

On the reverse side of the PCB there is only the other part of the connector that connects the two PCBs of the GeForce 7950 GX2 and a few power elements, including an Intersil ISL6560 controller which controls the GPU power supply. The memory power supply is managed by an Intersil ISL6549 chip. The GeForce 7950 GX2’s PCBs have in fact identical power circuits: the +12V voltage coming to the external connector of the top PCB is transferred to the bottom one via dedicated pins of the connecting strip.

The left part of this strip transfers power (wide contacts) as well as MIO interface signals (ordinary contacts). The right part is dedicated to PCI Express contacts. Note that the GeForce 7950 GX2 uses only one such connecting strip whereas the GeForce 7900 GX2 had two (because the GeForce 7900 GX2 was the basis of the Nvidia Quadro FX 5400 X2 model that supported four DVI outputs).

Unlike on GeForce 7900 GTX or GeForce 7900 GX2, the memory chips are placed in the shape of the letter L here. This helped make the PCB smaller but the wiring is somewhat more intricate due to the necessity to keep the lines between the GPU and memory the same size. You can see this clearly in the photo.

Nvidia’s new solution employs Samsung K4J52324QC-BC14 memory that works at 1.8V voltage and has a rated frequency of 700 (1400) MHz. Each PCB of a GeForce 7950 GX2 is equipped with eight GDDR3 chips, so the total amount of memory is 1GB (16 x 512Mb). However, you should be aware that 3D applications will only have 512 megabytes of graphics memory at their disposal even if you’ve configured a quad SLI subsystem with two GeForce 7950 GX2 cards. So, it’s not exactly correct to say that these graphics subsystem offer 1 or 2GB of graphics memory.

The GeForce 7950 GX2 clocks its memory at the same frequency as the GeForce 7900 GX2 does: 600 (1200) MHz. Such a low clock-rate means low memory bandwidth, and this may mean lower performance if you are using high display resolutions, especially with full-screen antialiasing. The low memory frequency was among the reasons why the four-processor Nvidia quad-SLI configuration did poorly in extreme graphics modes in our preview (for details see our article called Quadtet: Nvidia GeForce 7900 Quad SLI Performance Unveiled).

Cooling System

The cooling system has been greatly revised since the GeForce 7900 GX2. It is still made up of two identical single-slot coolers, but their design is simpler and the coolers themselves, more compact.

The cooler has an aluminum base, but contacts with the GPU die via a small copper spot. The flat heat pipe built into the base transfers heat to the heatsink, a many times folded sheet of copper. The ribs are placed at 45 degrees to the longer side of the PCB, so the hot air easily leaves the card.

 

The snapshot on the right clearly shows the groove of the channel the mentioned heat pipe lies in as well as the special juts against the memory chips. Very dense dark-gray thermal paste is used as a thermal interface between the cooler’s copper sole and the GPU die; the same paste is applied in between the cooler and the PCI Express x48 bridge.

The memory contacts the juts on the cooler’s base via special pads. These are not Nvidia’s traditional non-organic fiber pads soaked in thermal paste, but elastic pads that consist of two pink rubber-like pieces with a layer of thermal paste in between. They are so tightly pressed to the memory chips that go off along with the paint the marking is printed with on the chips.

Each cooler on the GeForce 7950 GX2 has a 2.16W blower (0.18A x 12V). The fan blades are small, so we suspect this blower has to be very fast to create a really strong airflow. A nod at the modding community, the fans have LED-based highlighting with Nvidia’s corporate green color.

This cooling system should be able to cope with the GeForce 7950 GX2, considering the low heat dissipation of the G71, yet we are rather dubious about its efficiency. In the GeForce 7900 GX2 the bottom cooler took its air in from special holes cut in the PCB. There are no such holes in the GeForce 7950 GX2, but the bottom cooler still nearly touches the top PCB. It obviously lacks air and we are afraid the bottom GPU may overheat if your system case is poorly ventilated, especially since the card throws the hot air back into the system. This cooling system is also going to be rather noisy with its two high-speed fans.

Noise

We measured the noisiness of our GeForce 7950 GX2 with Velleman DVM1326 digital sound level meter. It features 0.1dB resolution, allows measuring up to 130dB of noise and allows using A and C weighting.

At the time of this test the background noise level in the lab was 36dBA. The level of noise measures at a 1-meter distance from the test platform with a passive cooled graphics card equaled 40dBA. These are reference values, which we will use for the evaluation of the noise level generated by our testing participants.

Here is what we got from GeForce 7950 GX2:

In nominal workmode the card runs even quieter than GeForce 7900 GTX, because the fans of both coolers rotate at a low speed. Subjectively speaking, you cannot even hear GeForce 7950 GX2 against the background of other system components. As a rule, it is also quiet in 3D mode, however, if the core temperatures hit certain point, the thermal management system speeds up the cooling fans a lot and the level of generated noise grows up. In this case, GeForce 7950 GX2 turns out even noisier than Radeon X1900 XT/XTX from a 1-meter distance. At the same time, the noise generated by the graphics card fans can be very easily distinguished from the rest of the noises in a working system, because the fans are quite small, rotate at a very high speed and have a typical sounding. However, our subjective opinion is that the noise generated by the coolers of GeForce 7950 GX2 is not as unpleasant as the noise coming from the Radeon X1900 XT/XTX fan, because it is free from the typical “plastic” shade.

So, GeForce 7950 GX2 features quite acceptable noisiness and can only be heard when the GPUs get really hot. Therefore, you have to make sure that the case is very well ventilated and you might be able to avoid any uncomfortable audible effects.

Overclocking and 2D Quality

We tried to overclock GeForce 7950 GX2 to find out its frequency potential. Before we started our experiments we expected to achieve pretty good results for the graphics chips and not very good results for the memory, which featured 1.4ns access time – much lower than 1.1ns in GeForce 7900 GTX or Radeon X1900 XTX. As a result, we managed to get our graphics card to work stably at 590MHz chip frequency. The cooling system was definitely not the most efficient one, besides, the air intake for the bottom fan was slightly hindered, so the additional 90MHz we managed to get can be considered a pretty good result. These additional 90MHz should ensure s a pretty noticeable performance improvement for our GeForce 7950 GX2, at least in those tasks where the graphics memory will not turn into a limiting factor.

As for the memory, it turned out a real disappointment, as it worked fine only at 670 91340) MHz, i.e. it didn’t even reach the nominal value of 700 (1400) MHz. We even checked the contact between the memory chips and the heatsink foot: it was perfect. So, we believe that this low result could have been caused by not the best memory chips layout on the GeForce 7950 GX2 PCB. The memory chips working at such high frequencies are usually located in half circle around the GPU. On our card the engineers were probably trying to save some room, so they put the memory chips in an L-shaped manner. As a result, the connection between the chips and the GPU turned out far from optimal, which may have had negative influence on the memory stability at high frequencies.

As for the 2D image quality demonstrated by GeForce 7950 GX2, we cannot complain about anything, even in the maximum resolution mode of our lab monitor – 1800x1440@75Hz. The picture was crisp and clear in 1600x1200@85Hz. Note that in the multi-GPU mode when both graphics cores are involved, the card allows connecting only one display. The second DVI-I is disabled in this case. If you would like to use multi-monitor configurations, the card should be switched into multi-monitor mode. In this case all the standard Nvidia nView features will still be supported, however, only one GPU will be working and the gaming performance will drop down significantly.

Testbed and Methods

Unlike the situation with Quad-SLI, when we had very little time at our disposal (for details see our article called Quadtet: Nvidia GeForce 7900 Quad SLI Performance Unveiled), today we had all the time we needed to perform the full set of benchmarks on the Nvidia GeForce 7950 GX2.For our test session we used the following platform:

We set up the ATI and Nvidia drivers in the same way as always:

ATI Catalyst:

Nvidia ForceWare:

We selected the highest graphics quality settings in each game, identical for graphics cards from ATI and Nvidia. We did not edit the configuration files of the games. To measure the performance we either used the integrated tools of the games we tested in, or if there were none available, resorted to FRAPS utility. If it was possible, we measured minimal performance as well.

To load the video subsystem to the full extent and to minimize the influence of the CPU speed on the performance results we didn’t test the systems in the “pure speed” mode. We only ran the tests in “eye candy” mode with full-screen anti-aliasing and anisotropic filtering. We also ran the tests in “extreme eye candy” mode with enabled SLI AA 8x/16x or Super AA 8x/14x.

We enabled FSAA and AF from the game if possible. Otherwise we forced the necessary mode from the ATI Catalyst and Nvidia ForceWare graphics card driver. The same settings were used for extreme full-screen anti-aliasing modes.

These games and applications were used as benchmarks:

First-Person 3D Shooters

Third-Person 3D Shooters

Simulators

Strategies

Synthetic benchmarks

Since Nvidia GeForce 7950 GX2 is a dual-chip solution, we will compare it not only against the highest-performing single graphics cards such as ATI Radeon X1900 XTX and Nvidia GeForce 7900 GTX, but also against the corresponding CrossFire and SLI tandems.

GeForce 7950 GX2: Problems Revealed

Outside quad SLI, i.e. a single GeForce 7950 GX2, is actually none other but a common SLI tandem using one PCI Express slot instead of two, as usual. As a result, the testing went on smoothly, almost without any difficulties since Nvidia SLI technology has long been mature. The new Nvidia ForceWare version that belongs to the 90 series supports more than 240 applications in SLI mode. So no wonder that the new Nvidia solution proved almost 100% stable all the time.

Nevertheless, we still revealed a few small issues. In particular, we encountered some problems with lightning in X3: Reunion and F.E.A.R. games, although we couldn’t notice it immediately. Also, when we installed GeForce 7950 GX2 into the system, it was recognized as follows:

Although it doesn’t affect the functionality of our GeForce 7950 GX2 and most probably indicates an error in the .inf-file of the ForceWare driver.

So, GeForce 7950 GX2 is a pretty solid product free from “immaturity issues”, which are typical of new technologies. However you shouldn’t forget that this solution may be incompatible (and it is officially so) with a lot of contemporary mainboards. The new Nvidia graphics card is quite ready for a mainstream user. But before we draw any conclusions, let’s take a closer look at its performance in different applications.

Performance in Synthetic Benchmarks

First let’s take a look at a couple of synthetic tests. This will show us what to expect from the GeForce 7950 GX2 in games.

The GeForce 7950 GX2 delivers a much higher scene fill rate than the Radeon X1900 XTX due to the difference in their TMU count: 48 against 16. The graphics cores of the GeForce 7950 GX2 are clocked at a slightly higher frequency than the cores of the GeForce 7900 GT SLI, the fill rate they provide is higher in all cases. The new graphics card from Nvidia isn’t going to lack texturing speed even where the GeForce 7900 GTX used to fail, i.e. in applications that use large amounts of high-resolution textures or shaders with multiple texture lookups.

The GeForce 7950 GX2 also boast a tremendously high pixel shader performance, especially when it comes to executing simple shaders – it may deliver two times the performance of a Radeon X1900 XTX despite the same number of pixel processors (because the GeForce has more texture-mapping units). The gap isn’t that big when complex shaders are executed, especially those that render per-pixel lighting, yet it is large enough for the GeForce 7950 GX2 to claim superiority at processing shaders. Well, real-life games vary in the total number and complexity of shaders they use, so the overall picture of performance will be individual for each particular game.

Our Xbitmark test measures pixel shader performance, too, and its main advantage is in using various kinds of shaders, from almost purely math1ematic ones to shaders that are actively working with textures.

Here, the GeForce 7950 GX2 isn’t always ahead of the Radeon X1900 XTX: particularly, it is slower when there’s a lot of math1ematics to be done and on shaders with dynamic branches. But when high texturing speed is crucial, like in the NPR (hatch) shaders, the new solution from Nvidia has no opponents at all.

So, here’s what the GeForce 7950 GX2 can do in synthetic tests. Let’s see if it is as good in real-life games.

Performance in Gaming Benchmarks: First-Person 3D Shooters

Battlefield 2

The game doesn’t support extreme full-screen antialiasing modes, so we don’t have them here.

The GeForce 7950 GX2 doesn’t show its strength until 1600x1200, delivering an average performance like that of the single GeForce 7900 GTX. It’s only in the highest resolution that the new Nvidia graphics card nearly overtakes the Radeon X1900 XT CrossFire. It cannot reach the level of the GeForce 7900 GTX SLI because this SLI configuration has considerably higher GPU and memory frequencies.

We are discussing now the best consumer graphics solutions available today, so there’s no lack of performance with any of them. Even the single GeForce 7900 GTX yields over 90fps in 1600x1200 with enabled FSAA and anisotropic filtering which means high playing comfort for the gamer.

The Chronicles of Riddick

The GeForce 7950 GX2 is a little ahead of the GeForce 7900 GTX SLI in the lowest resolution, probably due to our using a new driver for it. The relatively low GPU and memory frequencies don’t allow the GeForce 7950 GX2 to remain in the lead in higher resolutions, yet it is faster than the GeForce 7900 GT SLI or Radeon X1900 XT CrossFire (the latter is handicapped by the game’s using OpenGL and dynamic stencil shadows).

So while the Radeon X1900 XTX cannot provide a comfortable speed in 1600x1200 at the max graphics quality settings, the GeForce 7950 GX2 gives you a satisfactory 100fps there.

The GeForce 7900 GTX SLI configuration stands out among the multiple-GPU solutions, delivering over 60fps in 1600x1200. The GeForce 7950 GX2 and the Radeon X1900 XT CrossFire have the same speed and allow using 8x FSAA in resolutions up to 1280x1024.

At the next level of FSAA the Radeon X1900 XT CrossFire takes the lead as it uses 14x Super AA which is less resource-consuming than 16x SLI AA. The GeForce 7950 GX2 has a good average frame rate in 1024x768 only – it is as fast as the GeForce 7900 GT SLI. So, 16x SLI AA mode still looks a luxury unavailable in high resolutions even to owners of two GeForce 7900 GTX.

Call of Duty

There are quite a lot of shader-based special effects in Call of Duty 2 and the game also appreciates a good memory controller. That’s why the Radeon X1900 XTX CrossFire with a total of 96 pixel processors wins here. However, the single Radeon X1900 XTX is hopelessly behind the GeForce 7950 GX2 in this test.

The GeForce 7950 GX2 has to content itself with the third place, yet its average performance is high enough for playing in every resolution at 4x FSAA plus 16x anisotropic filtering.

Strangely enough, the new dual-chip graphics card from Nvidia is only 2-4fps behind the GeForce 7900 GTX SLI in SLI AA 8x mode. But neither solution provides a comfortable frame rate in resolutions above 1024x768.

The most difficult test mode may only be interesting for owners of a Radeon X1900 XTX CrossFire configuration as it is the single graphics subsystem with an average performance of over 55fps here.

Yes, Nvidia’s 16x SLI AA renders a better-quality picture than ATI’s 14x Super AA, but none of the available Nvidia products can give you even 50fps in this test. It means that comfortable play is not possible.

Doom 3

The SLI configuration with two GeForce 7900 GTX cards is an obvious leader in Doom 3 since this game’s conditions (OpenGL plus stencil shadows) are favorable for the GeForce 7 architecture. The GeForce 7950 GX2 is somewhat slower, but it doesn’t matter much as it gives you a frame rate of over 80fps anyway. The Radeon X1900 XTX is competitive in Doom 3 , yet is hopelessly behind the new flagship from Nvidia.

You may find playing this game on a GeForce 7950 GX2 not very comfortable in 16xs mode or in 1600x1200 with enabled 8x FSAA. Note, however, that the Radeon X1900 XTX doesn’t support FSAA higher than 6x, and two such cards are hardly faster than a single 7950 GX2.

The Elder Scrolls IV: Oblivion

We don’t test this game with turned-on full-screen antialiasing because GeForce 6/7 based graphics cards do not support HDR alongside with FSAA whereas the game looks better with enabled HDR than without it.

Neither card can show its best in 1024x768 as they are all limited by the CPU performance. But beginning from 1280x1024 it is clear that the min frame rate of the GeForce 7950 GX2 is higher than that of the other cards or SLI configurations from Nvidia and is almost the same as the min frame rate of the single Radeon X1900 XTX. All other factors being the same, graphics cards with a high minimum fps ensure a higher comfort in this game, and the GeForce 7950 GX2 has something to be proud of. It is one of the best solutions available (the other one is Radeon X1900 XTX) to play TES IV: Oblivion .

In the open scenes of TES IV the GeForce 7950 GX2 feels the lack of memory bandwidth, especially in high resolutions. However, the new card is strong enough to keep the frame rate at 48fps even in 1280x1024. This is good considering the graphical complexity of this game.

This result, especially the minimum frame rate, is comparable with that of the Radeon X1900 XTX and GeForce 7900 GT SLI. The min frame rate parameter is sometimes even more important than the average performance of a card. For example, the speed of the GeForce 7900 GTX may bottom out to 15fps and this is the point where the game doesn’t run smoothly anymore. Such slowdowns are quite dangerous in combats when you want accurate control over the character in the presence of enemies. And it is in combat scenes that slowdowns are most likely to occur because the enemy models will have to be rendered in the frame.

This game is tested manually with the Fraps utility, so the numbers may be somewhat imprecise (particularly, we are not very sure about the low min speed of the Radeon X1900 XT CrossFire in 1600x1200).

Far Cry

We don’t get any useful information in our standard “eye candy” mode on the Pier map: all the multi-GPU solutions have the same performance across all the resolutions, meeting the barrier set by the system’s CPU. You may note, however, that this barrier goes somewhat lower for the GeForce 7950 GX2 than for the others due to its design or driver.

There is a surprise as we switch to 8x FSAA: the GeForce 7950 GX2 refuses to be slower than the GeForce 7900 GTX SLI subsystem that boasts better technical characteristics. Meanwhile, the GeForce 7900 GT SLI configuration, with frequencies similar to those of the GeForce 7950 GX2, has much worse results due to its smaller amount of graphics memory or to the older ForceWare driver it uses.

It’s all normal again as we switch to 16x SLI AA: the GeForce 7950 GX2 is not competing with the GeForce 7900 GTX SLI, but is only a little better than the GeForce 7900 GT SLI. The new graphics card doesn’t behave strangely as it did in 8x SLI AA mode, although 16x SLI AA should depend more on the parameters of the graphics subsystem than any other antialiasing mode.

Note that you again can only play normally on Nvidia’s cards in 1024x768 although Far Cry isn’t anything terrible for a modern graphics card of a high enough class, especially for a SLI tandem build on two top-end devices.

The participating graphics cards differ more on the Research map; the GeForce 7950 GX2 is considerably faster than the Radeon X1900 XTX in 1600x1200.

The odd behavior of the GeForce 7950 GX2 we saw on the Pier map can be observed on the Research level, too. It’s even more conspicuous: the new card leaves the GeForce 7900 GTX SLI behind by over 10%! The GeForce 7900 GT SLI configuration is far behind again, confirming our suspicions of that the new ForceWare driver is quite an improvement over the older version.

The graphics cards are generally higher here than on the Pier map, so all the multi-GPU solutions included in this review make all the display resolutions playable.

Being limited by its slow memory, the GeForce 7950 GX2 cannot surprise us anymore in 16x SLI AA mode. It still manages to be within 8-10% from the GeForce 7900 GTX SLI. You can play this game on the new Nvidia card in 1280x1024 at such settings (but this is only true for Far Cry ’s closed scenes).

All the participating graphics cards are roughly similar in the lowest resolution, but the GeForce 7950 GX2 takes the lead in 1280x1024. Unfortunately, the GeForce 7 architecture doesn’t support FSAA and HDR simultaneously, so you have to choose between getting an anti-aliased picture and better color representation.

The same goes for the Research map where the GeForce 7950 GX2 has an average speed of 85fps and higher in HDR mode. It beats the Radeon X1900 XTX here.

F.E.A.R.

The 96 pixel processors put the Radeon X1900 XT CrossFire in the lead in 1024x768, but in higher resolutions it is for some reason slower than Nvidia’s GeForce 7900 GTX SLI and GeForce 7950 GX2. The latter two go neck and neck up to 1600x1200 resolution where the GeForce 7900 GTX SLI wins by 10% due to its higher memory frequency.

In other words, we’ve got a situation similar to what we saw in Far Cry . The efficient new ForceWare driver must be the reason for the high performance of the GeForce 7950 GX2 which has rather modest technical characteristics.

As soon as we turn on 8x FSAA, the GeForce 7950 GX2 falls behind the GeForce 7900 GTX SLI in all the resolutions, but by no more than 5%. The new card’s min speed in 1280x1024 is considerably lower than that of the fastest dual-card SLI config.

The Radeon X1900 XT CrossFire also comes up among the leaders here – it had been slower than Nvidia’s solutions in the previous test.

The more difficult antialiasing modes are too hard for today’s multi-GPU solutions in this game. Note, however, that the GeForce 7950 GX2 is obviously slower than the GeForce 7900 GTX SLI or Radeon X1900 XT CrossFire here.

Ghost Recon: Advanced Warfighter

The full name of this project developed by Red Storm Entertainment/GRIN and published by Ubisoft Entertainment is Tom Clancy’s Ghost Recon: Advanced Warfighter . The game is a sequel to the rather popular tactical shooter Ghost Recon , telling you another story about the Ghosts, an elite squad equipped up to the latest developments made in the framework of the Future Force Warrior program.

The game runs on Diesel Engine 6.0. The engine’s characteristics and capabilities are largely kept secret by the developer who is, however, known to have close relationships with Nvidia. We are familiar with some details, though. The game supports high dynamic range mode (HDR) and uses a deferred shadowing method that allows rendering the lighting of a scene after its geometry has been rendered. In theory, this method is faster, but it is not compatible with FSAA. The game is rather a heavy application in terms of graphics complexity and thus suits well for testing modern graphics hardware. Moreover, the Tom Clancy’s series is highly popular among gamers, which is the main reason for our including it into our selection of benchmarks.

We found out during the tests that the game doesn’t permit to use high resolutions on graphics subsystems that have less than 512 megabytes of memory.

Multi-GPU technologies work incorrectly in this game, leading to a colossal performance hit. The new Nvidia ForceWare driver (version 91.29) solves this problem, so the GeForce 7950 GX2 has no problems whatsoever. It runs the game fast enough even in 1600x1200 and the frame rate is never lower than 51fps even in the hardest scenes. No single-chip graphics card available can do the same. The GeForce 7900 GTX can be used at 1280x1024 resolution, while the speed of the Radeon X1900 XTX is too low even in 1024x768.

Half-Life 2

The CPU limits the speed of every single-card and multi-GPU subsystem in this test. As before, this barrier goes a little higher for ATI Technologies’ solutions.

Among Nvidia’s solutions, the GeForce 7950 GX2 is again the best, leaving the GeForce 7900 GTX SLI behind, not to mention the rivaling Radeon X1900 XTX. The new graphics card can be used for playing Half-Life 2 in any resolution with enabled 8x SLI AA. The Radeon X1900 XT CrossFire has better results, but it would cost you $900-1000!

The original Half-Life 2 isn’t a very difficult test for today’s graphics cards. You can use the highest FSAA modes in resolutions up to 1280x1024 on Nvidia’s flagship products. Owners of a Radeon X1900 XT CrossFire rig can also use 1600x1200.

Half-Life 2: Lost Coast

If you have a flagship multi-GPU solution from Nvidia, Half-Life 2: Lost Coast allows using much heavier and resource-hungry FSAA modes in resolutions up to 1280x1024. If you have a Radeon X1900 XT CrossFire tandem, the top FSAA modes are available to you in all resolutions.

The GeForce 7900 GTX SLI is the only graphics subsystem that provides an acceptable frame rate in 1280x1024. The rest of the participating solutions only make the resolution of 1024x768 playable. The results of the GeForce 7950 GX2 are close to those of the Radeon X1900 XT CrossFire.

The Radeon X1900 XT CrossFire and the GeForce 7900 GTX SLI are the only graphics subsystems that provide a comfortable performance in Half-Life 2: Lost Coast when extreme FSAA modes are enabled, and only in 1024x768. The GeForce 7950 GX2 is greatly limited by its relatively slow memory, yet it is ahead of the GeForce 7900 GT SLI – almost two times faster in 1600x1200.

Project: Snowblind

This game is incompatible with multi-GPU technologies – turning on SLI or CrossFire leads to a considerable performance hit here.

Everything works right in modes intended for higher image quality or extreme FSAA. The GeForce 7950 GX2 has an excellent result, being as fast as the Radeon X1900 XT CrossFire at a much lower cost. The game is rather simple as today’s games go, so you’ve got enough speed in every resolution.

The GeForce 7950 GX2 is no more than 10-15% behind the GeForce 7900 GTX SLI in 16x SLI AA mode. Nvidia’s solutions deliver a playable frame rate in all resolutions below 1600x1200. The Radeon X1900 XT CrossFire makes the highest resolution playable, too, even though with a slightly worse antialiasing quality.

Quake 4

The multi-GPU solutions readily reach the performance ceiling in Quake 4 in the standard resolutions with enabled 4x FSAA. The GeForce 7950 GX2 is a little slower than the Radeon X1900 XT CrossFire and GeForce 7900 GTX SLI, but this doesn’t matter much as all the dual-processor solutions are capable of delivering a comfortable 88-98fps on average. The gap between the GeForce 7950 GX2 and the single-chip flagship products from ATI and Nvidia is about 20-30%. That is, the latter are no real competitors to the new dual-chip graphics card in this test.

The GeForce 7950 GX2 doesn’t show any miracles here and takes its place between the GeForce 7900 GTX SLI and GeForce 7900 GT SLI. The new card allows using 1280x1024 resolution in Quake 4 at this level of FSAA. Well, you can even try to play in 1600x1200 on your GeForce 7950 GX2, but the speed may sink below comfortable level in action-heavy scenes which may mean lethal outcome for your character.

You are limited to 1024x768 resolution if you play this game on an Nvidia card – the speed is lower than 55fps in the other display modes. It’s quite different with the Radeon X1900 XT CrossFire which shows a superb performance in 1600x1200 with enabled 14x SuperAA.

Serious Sam 2

Average and minimum speeds differ greatly in Serious Sam 2 . The most powerful solution from Nvidia, the SLI configuration with two GeForce 7900 GTX cards, has the best average result, but its min speed is below 25fps in 1024x768 and below 20fps in higher resolutions. Although you can run the game on a GeForce 7950 GX2 with enabled 4x FSAA, the game may get jerky at times.

Note that the immediate rival to the GeForce 7950 GX2, the Radeon X1900 XTX has a min speed of about 30fps in 1024x768. So it ensures a smoother game play at a lower average speed, and this despite the not very Radeon-friendly rendering methods employed by the developers of Serious Sam2 .

The multi-GPU configurations Radeon X1900 XT CrossFire and GeForce 7900 GTX SLI deliver a nearly comfortable performance here. The other multi-GPU solutions are unable to do that. Judging by the average speed, the GeForce 7950 GX2 is close to that, buts its min speed is too low – a sudden slowdown to 14-15fps may mean death for your character during a combat.

In the hardest mode it’s only the Radeon X1900 XT CrossFire that can notch the 50fps mark in 1024x768. The min speed is only 16fps at that which means slowdowns in complex game scenes. In other words, Serious Sam 2 is not very friendly towards extreme full-screen antialiasing modes. Well, you can hardly play it in resolutions higher than 1024x768 even with ordinary 4x FSAA!

Performance in Gaming Benchmarks: Third-Person 3D Shooters

Splinter Cell: Chaos Theory

The GeForce 7950 GX2 is as fast as the GeForce 7900 GT SLI and better than the Radeon X1900 XTX in this test. The new card also challenges the Radeon X1900 XT CrossFire in low resolutions. But besides the performance factor, the GeForce 7950 GX2 is easier to use than any dual-card solution because it doesn’t require two PCI Express x16 slots and is compatible with mainboard on chipsets from various manufacturers.

Note also that the minimum frame rate of the new card is considerably higher than that of the GeForce 7900 GTX SLI, which seems to be the new driver’s doing.

The same is true for the 8x SLI AA mode. The GeForce 7950 GX2 ensures a bigger speed reserve than the GeForce 7900 GTX SLI and is competing with the monstrous Radeon X1900 XT CrossFire. The new card runs Splinter Cell: Chaos Theory at a comfortable speed in 1600x1200 with high-quality 8x SLI AA which is unavailable to owners of single cards. Its 30fps should suffice for a 3D shooter with third-person view.

Performance in Gaming Benchmarks: Simulators

Pacific Fighters

This game’s engine is GeForce-oriented, so Nvidia’s graphics cards have always had better results here than same-class solutions on ATI’s GPUs.

Despite FSAA, Nvidia’s cards all reach the performance ceiling in resolutions below 1600x1200. In the highest resolution, however, we can see that no single-processor card can match the GeForce 7950 GX2. The GeForce 7900 GT SLI subsystem, the only multi-GPU solution in this review that is similar to the new card in price, is 10% slower than it.

The overall picture looks like that: all the participating graphics cards, including the Radeon X1900 XTX and GeForce 7900 GTX, deliver a comfortable frame rate in the 4x FSAA + 16x AF mode, although the mentioned two have an alarmingly low minimum speed.

There’s not much difference between Nvidia’s multi-processor solutions in 8x SLI AA mode. For some unclear reason the SLI rig with two GeForce 7900 GT turns in the best min frame rate in two out of the three resolutions.

The Radeon X1900 XT CrossFire is quite fast, too, but it doesn’t support vertex texturing for rendering the water surface with the highest possible quality.

When we switch to the next level of antialiasing (SLI AA 16x and Super AA 14x), the resolution of 1600x1200 becomes unplayable while the gap between Nvidia’s and ATI’s cards becomes smaller. All the multi-GPU systems included in this review allow playing with comfort in 1280x1024, although the water surface as rendered by the Radeon X1900 XT CrossFire is lower quality.

X3: Reunion

Contrary to Pacific Fighters , X3: Reunion prefers graphics cards on ATI’s Radeon X1000 processors: even the single Radeon X1900 XTX beats the SLI-based subsystems in the two lower resolutions and matches them in 1600x1200!

The GeForce 7950 GX2 is closer in speed to the single GeForce 7900 GTX and is slower than the GeForce 7900 GT SLI in 1024x768 where the graphics memory has the least influence on the overall result. In 1600x1200, however, the GeForce 7900 GT SLI falls behind the GeForce 7950 GX2, perhaps due to its having less graphics memory.

The results suggest that the efficiency of Nvidia SLI technology is near zero in this game, but this doesn’t affect your playing comfort. You can play in 1600x1200 with enabled 4x FSAA and the Universe around your spaceship will be revolving as smoothly as you may wish.

Performance in Gaming Benchmarks: Strategies

Age of Empires 3

We don’t publish the results the ATI CrossFire platform in extreme FSAA modes due to the problem that arises in this game if you try to use them.

It is a weird picture: the participating graphics solutions all have nearly the same performance in every resolution. The single Radeon X1900 XT has the best minimum speed; the Radeon X1900 XT CrossFire tandem has a lower min speed, probably due to the overhead for synchronizing the two cards in CrossFire mode.

We’ve got all the best graphics hardware in this test, so the average performance is always on a comfortable level with enabled 4x FSAA.

Warhammer 40.000: Dawn of War

Like almost every game that uses stencil shadows, Dawn of War runs the fastest on Nvidia’s GeForce 6 and 7 series cards. Moreover, the game doesn’t even use the SM2.0 features, not to mention SM3.0. The GeForce 7950 GX2 turns in one of the best results in this game, being just a little slower than the GeForce 7900 GTX SLI which is way more expensive and requires a SLI-compatible mainboard. The results of the GeForce 7950 GX2 are comparable with those of the GeForce 7900 GT SLI, but the latter is less practical just like any classic dual-card multi-GPU rig.

The average performance of the Radeon X1900 XT CrossFire is somewhere near the same point, but its speed goes down more in difficult game scenes because this graphics architecture cannot accelerate stencil shadows rendering.

Nvidia’s solutions including GeForce 7950 GX2, have the same performance in 8x SLI AA mode.

Thanks to its new driver, the GeForce 7950 GX2 manages to compete with the GeForce 7900 GTX SLI, both delivering a playable frame rate in all the standard resolutions. The GeForce 7900 GT SLI configuration, comparable in price with the GeForce 7950 GX2, is not fast enough for 1600x1200.

We remind you that we used ForceWare 84.21 for the classic SLI systems and ForceWare 91.29 for the GeForce 7950 GX. The performance picture would probably be different if we used the new 90 series driver for all of Nvidia’s solutions.

In 16 SLI AA mode the user has to limit himself to 1024x768 resolution. The GeForce 7950 GX2 cannot keep the same pace with the GeForce 7900 GTX SLI here, the gap amounting to about 10%.

Performance in Gaming Benchmarks: Synthetic Tests

Futuremark 3DMark05 build 1.2.0

Although GeForce 7950 GX2 uses a new driver that belongs to the ForceWare 90 series, its result is only 147 points ahead of the GeForce 7900 GT SLI. If we compare these two solutions from the technical specifications standpoint, the result like that will be quite logical, because GeForce 7950 GX2 has faster GPU than GeForce 7900 GT SLI, but its memory is slower.

If we compare our hero against Radeon X1900 XTX, the new Nvidia solution will be 1258 points ahead, which is about 10% (since the overall performance rate lies around 12,000). Not very impressive I should say, since the baby features two graphics processors onboard, but it is a victory anyway.

In the regular eye candy mode the newcomer outperforms GeForce 7900 GT SLI by only 5% in 1280x1024. In 1600x1200 this advantage doubles: 10%.

The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI starts growing only when we enabled SLI AA 8x and reaches 20%. Although we are talking about the today’s highest-performance graphics systems, the best performance they can provide is 40fps on average. In other words, it is absolutely insufficient for the next-generation games with enabled extreme anti-aliasing modes.

In SLI AA 16x mode GeForce 7950 GX2 retains its intermediate position between GeForce 7900 GTX SLI and GeForce 7900 GT SLI.

Game 2 test is considerably less overwhelming but nevertheless GeForce 7950 GX2 falls much farther behind GeForce 7900 GTX SLI than in Game 1 test.

The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI becomes more evident and reaches 10%.

With higher quality anti-aliasing modes enabled the situation is practically the same, only Radeon X1900 XT CrossFire suddenly dashes forward because its SuperAA 14x requires less resources than SLI AA 16x.

In Game 3 test GeForce 7950 GX2 remains a little ahead of GeForce 7900 GT SLI and far ahead of Radeon X1900 XTX (about 30%).

When we switch to SLI AA 8x, nothing changes. Like in the previous cases GeForce 7950 GX2 holds the position between GeForce 7900 GT SLI and GeForce 7900 GTX SLI.

The same situation can be observed with SLI AA 16x enabled.

If we compare the total 3DMark05 score with the results of individual game tests with enabled FSAA 4x, we will see that it is absolutely correct: GeForce 7950 GX2 is just a little bit ahead of GeForce 7900 GT SLI.

As for the extreme anti-aliasing modes, the new Nvidia solution may show some really impressive results. It is important to note though that the newcomer owes its great performance to the new more advanced driver version.

Futuremark 3DMark06 build 1.0.2

The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI is even more vivid in 3DMark06: the newcomer is 342 points ahead, while the total score is much lower than in 3DMark05. Besides the graphics chip frequency, it is probably the smaller amount of graphics memory by GeForce 7900 GT SLI that matters in this test suite, because 3DMark06 is known to be sensitive to graphics memory subsystem. Despite the 48 pixel processors, Radeon X1900 XTX loses to GeForce 7950 GX2 by the good 1985 points, because the performance in this test suite doesn’t depend only on the pixel processors.

If we consider the results of the SM2.0 tests, the performance difference between GeForce 7900 GT SLI and GeForce 7950 GX2 will be as evident as in the total score chart: the latter is 203 point ahead. Since the overall performance level lies around 4,000 point, this advantage is quite noticeable.

The gap is almost as big in the SM3.0/HDR tests: GeForce 7950 GX2 is 191 point ahead of GeForce 7900 GT SLI. Although GeForce 7950 GX2 and Radeon X1900 XTX feature the same amount of pixel processors, the latter yields the good 849 points to the Nvidia rival. The latter features a lot of functional units such as TMU and ROP, and the performance in this set of tests depends not only on the pixel shader performance.

Since GeForce 7900 GT SLI tandem has only 256MB of graphics memory available to applications, it fails to pass the first SM2.0 graphics test in 1600x1200 with enabled FSAA 4x. in lower resolutions it yields to GeForce 7950 GX2 somewhere between 3% and 10%. For Radeon X1900 XTX the gap makes from 25% to 40% depending on the resolution, and reaches its biggest size in 1024x768, where the performance of GeForce 7950 GX2 is not limited by the slower memory.

The advantage of GeForce 7950 GX2 over GeForce 7900 GT SLI stands out more in SM2.0 graphics test, where it hits 20%. This test is probably less sensitive to fillrate, and besides the new ForceWare driver kicks in and affects the results. Radeon X1900 XTX cannot compete with GeForce 7950 GX2 even despite the little dependence on the fillrate. The solution with pixel processors : TMU : ROP as 3:1:1 cannot really compete with the product featuring 48 pixel processors, the same amount of TMUs and 32 rasterization units.

So, Nvidia GeForce 7950 GX2 outperforms GeForce 7900 GT SLI in individual SM2.0 tests much more than we see in the total score chart. However, we shouldn’t forget that in the former case we used default 3DMark06 settings without full-screen anti-aliasing.

Conclusion

Well, we have completed our extensive testing of the new Nvidia GeForce 7950 GX2 graphics accelerator. It is time for us to make some conclusions. Did Nvidia manage to win back the leader’s laurels? Has the newcomer become the world’s fastest single graphics card for $649?

GeForce 7950 GX2: Winners Come in Pairs

The results obtained during our test session let us answer “yes” to both these questions. It is true, in most cases GeForce 7950 GX2 managed to outpace its main rival, ATI Radeon X1900 XTX, that costs about $100-$150 less. The newcomer won a convincing victory in 15 benchmarks out of 20, and in two tests it performed equally fast with ATI Radeon X1900 XTX. It is quite logical: contemporary gaming performance doesn’t depend only on the pixel shader processing speed. There are some other factors involved, such as texturing speed, for example.

Although the rivals feature the same amount of units responsible for pixel shader processing – both ATI Radeon X1900 XTX and Nvidia GeForce 7950 GX2 have 48 units like that – the Nvidia solution is quite far ahead of the ATI one when it comes to TMUs and rasterizing units. GeForce 7950 GX2 has 48 TMUs and 32 ROPs, which eliminates all potential bottlenecks typical of Radeon X1900 XTX with its 16 TMUs and 16 ROPs. As a result, with the joint power and resources of two G71 GPUs, GeForce 7950 GX2 won even those battles where GeForce 7900 GTX capitulated.

Thanks to the new ForceWare driver series, GeForce 7950 GX2 managed to compete on almost equal terms with such expensive solutions as GeForce 7900 GTX SLI and even Radeon X1900 XT CrossFire. However, when the new ForceWare driver for the rest of the GeForce 7 graphics card family comes out, their performance will grow up as well. Besides, ATI Catalyst developers may also do something with their software to speed up Radeon based solutions.

Besides that, the newcomer performed very well in higher-quality full-screen anti-aliasing modes than the standard FSAA 4x, which used to be the privilege of the expensive SLI and CrossFire tandem owners. The new Nvidia graphics accelerator is beyond any competition here because none of the currently available single-chip cards supports high-quality anti-aliasing. Those of you who have a Radeon X1900 XTX may get close to the anti-aliasing quality provided by the new GeForce 7950 GX2 by using FSAA 6x and Temporal Antialiasing supported by ATI Technologies’ cards.

Nobody Is Perfect: Achilles’ Heels

As we have already mentioned, GeForce 7950 GX2 yielded to Radeon X1900 XTX only in three tests out of 20. These three exceptions are Half-Life 2, X3: Reunion and Project: Snowblind. However, if in the first two games it is the peculiarities of the game itself that determined Nvidia’s loss, then in the third game we have a great illustration of GeForce 7950 GX2’s weakness.

The thing is that since GeForce 7950 GX2 is in fact an SLI tandem put together on a single PCB using one PCI Express x16 slot, it has to rely solely on SLI support in the ForceWare driver and game engine. This is exactly the weak point I am talking about: if there is no appropriate support, the performance of the new solution may not only drop down to the level of a single GeForce 7900 GT selling for $299. It can drop even lower, like in Project: Snowblind. Although this is the only case we detected throughout this test session, no one is guaranteed to be safe from the same situation in any other game that will be coming out soon. I just hope that Nvidia will work closely with the game developers: the user who spent so much money of a piece of hardware has the right to get the best out of this purchase, really.

GeForce 7950 GX2 has a few other drawbacks. In particular, there are very few mainboards today that support this new Nvidia solution. As we have already mentioned, at the time we were working on this review, the list of mainboards supporting this graphics adapter featured only 39 mainboards, which is not much at all, keeping in mind that there are tons of models with PCI Express x16 support out there. Of course, the list will continue growing and hopefully it will happen fast enough, but the current situation with GeForce 7950 GX2 compatibility still leaves much to be desired. At the same time, Radeon X1900 XTX provides pretty high performance in most games with FSAA 4x setting and works flawlessly on almost any mainboard with PCI Express x16 slot.

Another drawback of the new GeForce 7950 GX2 is not a significant one but may cause nasty problems to some users. I am talking about multi-monitor configurations support. Since Nvidia SLI technology (like ATI CrossFire) supports only one display in case both GPUs are involved, the owners of multi-monitor configurations will have to switch from multi-GPU mode to multi-monitor mode every time they finish playing games and vice versa. Of course, if you often switch between games and any other work that requires multi-monitor support, this may become a very annoying issue for you.

Summary

Still, compared with the GeForce 7900 GX2, which can hardly be used (and is not even available) outside the ready quad SLI systems, the new GeForce 7950 GX2 is a huge step forward. The new Nvidia graphics accelerator is quite compact in size to fit into a standard PC case, boasts unique performance for a single graphics card and supports FSAA modes that have always been the privilege of expensive SLI and CrossFire systems. Moreover, it has quite a bit of potential to be used within a quad SLI platform later on and thus to ensure an even higher level of performance.

The solution is not free from a few drawbacks, but it is typical of any new technology. So we hope that Nvidia will eventually eliminate the compatibility issues and the user will get the best high-end graphics accelerator. Moreover, the launch of GeForce 7950 GX2 may stimulate ATI to release something of the kind, and the end-user will definitely benefit from the competition in this market segment.

Highs:

Lows: