by Alexey Stepin
04/24/2006 | 12:53 PM
Finding itself no opponents after the release of the GeForce 7800 series, which offered a much higher performance than the Radeon X850, Nvidia could go setting prices for its top-end graphics cards just it wanted, putting a $599 tag on the flagship product, and a $499 tag on the less advanced model. That was about $50 more expensive than the earlier price records for graphics cards targeted at performance-conscious users.
The high prices were due not only to the lack of worthy alternatives on the market but also to the relatively high manufacturing cost of the 110nm G70 chip which was the heart of all GeForce 7800 series graphics cards. However, Nvidia had to reconsider the pricing after the arrival of the Radeon X1800 and to do it once again after the Radeon X1900 had been released. But Nvidia wasn’t just idly enjoying it success – it was moving forward. Shortly afterwards – in about half a year since the commercial release of the GeForce 7800 – the company got its thinner, 90nm tech process with low-k dielectrics (not used by Nvidia previously) up and running.
The new tech process ensured a considerable increase in the frequency potential of the GeForce 7900 GTX in comparison with its predecessors and helped make the chip smaller. The overall GPU design had also been optimized and the total number of chip transistors had been reduced in comparison with the GeForce 7800. All this means that Nvidia can now sell its top-end products for less money but earn the same profits, on a condition that the chip yield is as high as it has been with the older chips.
It is noteworthy fact that, though not much faster than the GeForce 7800 GTX 512, the GeForce 7900 GTX costs $150 less. Even more impressive is the GeForce 7900 GT, a card with a recommended price of $299, yet with better characteristics than the GeForce 7800 GTX that used to come for as much as $599 only 10 months ago!
This time Nvidia didn’t disable any execution units in the GT-suffixed product, so frequency is the single difference between the GeForce 7900 GT and the more expensive GTX. The GeForce 7900 GT features 24 pixel processors, 24 texture-mapping units (TMUs), 8 vertex processors, and 16 raster operators (ROPs). The developer recommends 450MHz GPU and 1320MHz memory frequencies for this product which, again, are higher than the frequencies of the company’s best product of less than a year ago.
Unlike the GeForce 7900 GTX, the GeForce 7900 GT uses a unique PCB design, developed almost from scratch.
The new card is shorter than the GeForce 7800 (for details please see our article called NVIDIA GeForce 7800 GT: Full-Throttle Graphics for $449) because the GPU and memory chips have moved along with their accompanying components closer to the DVI-I connectors; the previously empty part of the card is now densely populated. The graphics memory wiring has been redesigned for GDDR3 chips in new 136-pin FBGA packages (Nvidia used 144-pin chips earlier). The video-capture chip is missing here, although there’s place reserved for it on the PCB. It may probably be installed on serially produced cards.
The power circuitry has been greatly simplified. It now includes fewer power elements because the G71 needs less power than the G70; the number of electrolytic capacitors is almost the same, though. The cooler’s fan is still connected via a 2-pin plug while the senior members of the GeForce 7800 and 7900 families use an intelligent 4-pin connection. So, you shouldn’t expect the fan speed control system to be very clever, but there shouldn’t be too much noise, either, considering the low heat dissipation of the G71 chip clocked at a reduced frequency.
This sample of the graphics processor is dated the 3rd week of 2006, i.e. it is older than the chips installed on our samples of the GeForce 7900 GTX. Perhaps early batches of the G71 didn’t have a high frequency potential, but anyway the GeForce 7900 GT is going to be manufactured out of chips that can’t pass a frequency check for installation on GeForce 7900 GTX cards. As mentioned above, the GeForce 7900 GT has the same number of active pixel and vertex processors as the GeForce 7900 GTX: 24 and 8, respectively. According to the official specification, the GeForce 7900 GT’s pixel processors and raster operators are clocked at 450MHz and vertex processors at 470MHz. The chip lacks a protective frame, but it’s not a big problem since the GeForce 7900 GT employs a smaller and lighter cooler than the one they install on the GeForce 7900 GTX.
The card has Samsung’s K4J55323QG-BC14 chips on board. These chips have an 8Mb x 32 structure, 256Mb capacity, 1.8V voltage, and are rated to work at 700 (1400) MHz. The total of graphics memory is 256 megabytes; its clock rate is 660 (1320) MHz or a little lower than the recommended 700 (1400) MHz. The peak memory bandwidth of the GeForce 7900 GT is much higher than that of the GeForce 7800 GT: 42.2GB/s against 32GB/s.
The technical characteristics of the GeForce 7900 GT and GeForce 7800 GTX are very similar, so we can expect them to be in the same level of performance in games.
A very simple and compact cooling system is installed on the card; it looks more like a cooler for a mainstream or even an entry-level product.
The cooler consists of a copper base with a glued copper ribbing. The whole arrangement is covered with a plastic air-directing casing and is completed with a small blower about 45mm in diameter. The fan consumes 0.19A which may mean too much noise considering its tiny size. The fan’s blades are made of UV-reactive plastic and shine in ultraviolet light. The cooler is secured on the card by means of four spring-loaded screws.
We’ve got the familiar dark-gray thermal paste in between the heatsink and the GPU die. The memory of the GeForce 7900 GT is not cooled at all notwithstanding its rather high clock rate. Previously we only met 500 (1000) MHz memory without any cooling, but the new chips in 136-pin packages are probably less hot. Anyway, proper ventilation inside your PC case is a must if you are going to use a GeForce 7900 GT, and you may want to replace its standard cooler with something more efficient if you are going to overclock it.
Such a simplistic cooler is an indication of the low power consumption of Nvidia’s new graphics processor. For example, the reference cooler on the GeForce 7800 GTX, although single-slot in design, was a rather intricate thing with heat pipes and intelligent fan speed control. But the GeForce 7800 GTX graphics processor worked at a lower frequency: 430MHz as opposed to 450MHz.
We have already tested the power consumption in heat dissipation of the GeForce 7900 graphics cards family in our previous article called Nvidia’s Repartee: GeForce 7900 GTX Graphics Card Review.
The noise characteristics of the GeForce 7900 GT may seem rather poor if you compare it with the GeForce 7900 GTX. The small cooler installed on this card is always working at a high speed and is perfectly audible against the rest of the system sounds (from the CPU cooler, power supply and hard drives). We didn’t spot any trace of a speed management system, but perhaps it is only missing on test samples of the card. The fan speed can be controlled with the latest version of RivaTuner, but be careful not to reduce it too much or the card may die from overheat.
Frankly speaking, we don’t think much of the GeForce 7900 cooler. Small and with a tiny fan, it is very noisy, but is not very efficient. If you are planning to overclock your GeForce 7900 GT or want to have a silent computer, consider replacing the standard cooler with something better. We suppose some graphics card manufacturers are going to equip their GeForce 7900 GT with original coolers of their own design.
The GeForce 7900 GT is made out of those G71 chips that didn’t pass a frequency check for installation on GeForce 7900 GTX. That’s why we didn’t expect we would be able to raise the GPU frequency of the card even to 600MHz. That was really so. The maximum stable frequencies of the GPU and memory were 560MHz and 800 (1600) MHz (the card’s standard cooler was aided with an additional 120mm fan in this overclocking test). This is a good enough result considering the very simple cooler the GeForce 7900 GT is equipped with. Of course, overclockability varies from sample to sample, but at its official price of $299 the card is anyway going to be a real gift for any overclocker.
The new graphics card from Nvidia also yielded an impeccable 2D picture in all the display modes supported by our laboratory monitor, including 1800x1440@75Hz. We didn’t observe any fuzziness of test or shadowing.
Since we had two GeForce 7900 GTX and two GeForce 7900 GT graphics cards at our disposal, we decided to also investigate the performance of the corresponding SLI-tandems and compare the results against those of the ATI Radeon X1900 XT CrossFire and GeForce 7800 GTX SLI. We used the following mainboards as a basis for our test platforms:
The remaining components were the same for both test platforms:
We selected the highest graphics quality settings in each game, the same for ATI’s and Nvidia’s solutions, except for the Pacific Fighters flight simulator which requires vertex texturing support to enable its Shader Model 3.0 mode. The Radeon X1000 family doesn’t support this feature and runs the game in the Shader Model 2.0 mode. We did not edit the games’ configuration files. If possible, we used the games’ built-in benchmarking tools and if not, we measured the frame rate with the FRAPS utility. We measured minimal fps rates 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. Instead, we added two new modes to our traditional “eye candy” settings (4x FSAA + 16x anisotropic filtering). These were the resource-hungry aliasing modes, such as Super AA/SLI AA 8x + AF 16x and Super AA 14x/SLI AA 16x + AF 16x. We turned on the 4x FSAA + 16x AF mode from the game’s own menu if it was possible. Otherwise, we forced the necessary mode from the ATI Catalyst and Nvidia ForceWare driver. The drivers were configured as follows:
ATI Catalyst :
These games and applications were used as performance benchmarks:
First-Person 3D Shooters
Third-Person 3D Shooters
Battlefield 2 still does not support extreme full-screen antialiasing modes, so we limited ourselves to the 4x FSAA + 16x AF mode.
Just as we expected, the GeForce 7900 GT is about as fast as the GeForce 7800 GTX. And this is true for the single cards as well as for the SLI couples. Well, the G70 and G71 chips are architecturally identical whereas the difference in clock rates between the old and new cards from Nvidia isn’t so big as to lead to a significant difference in their performance. Even in 1600x1200 the newer card is only 5% faster.
Curiously enough, the single GeForce 7900 GT is considerably slower than the single Radeon X1800 XT, but two such cards in multi-GPU mode aren’t any worse than the two Radeon X1800 XT and provide over 110fps in the highest resolution.
The GeForce 7900 GT isn’t far ahead of the GeForce 7800 GTX at 4x FSAA, but the gap grows bigger when we switch to the more resource-consuming antialiasing modes – most likely due to the higher memory frequency of the new graphics card. In the SLI AA 8x mode the GeForce 7900 GT SLI is faster than the Radeon X1800 XT CrossFire platform which features better technical characteristics but is far less economical. Anyway, 1280x1024 remains the maximum resolution for all the multi-GPU configurations in which the game runs at an acceptably high speed.
Except for 1024x768 resolution, the GeForce 7900 GT and the GeForce 7800 GTX are equals and are both much slower than the Radeon X1800 XT which boasts high operating frequencies and a ring-bus memory controller. None of these cards can ensure a really comfortable frame rate in high resolutions with enabled full-screen antialiasing; it’s only in 1024x768 that you get something like 60-70fps.
Alas, the SLI configurations based on GeForce 7800 GTX and GeForce 7900 GT only push the bar up to 1280x1024 resolution whereas the Radeon X1800 XT CrossFire maintains an average speed of about 60fps in 1600x1200, or in 1024x768 if you use 8x Super AA.
The GeForce 7900 GT and GeForce 7800 GTX cards produce coinciding results under normal conditions (also at 4x FSAA). The difference is 1-2fps while the average frame rates are 50-80fps.
The GeForce 7900 GT SLI tandem does much better in the 8x SLI AA mode, especially in high resolutions. The new card is sometimes 20% and more ahead of the older one and is competitive against the Radeon X1800 XT CrossFire despite the latter’s higher frequencies and twice the amount of graphics memory. You should bear in mind the overall orientation of the Doom 3 engine, which uses OpenGL and stencil shadows, towards Nvidia’s GeForce 7 architecture.
The gap between the new and older cards is diminishing in the 16x SLI AA mode as the display resolution grows. The memory load is too high then and the 60 (120) MHz frequency bonus doesn’t matter much. The Radeon X1800 XT CrossFire is in the lead, but only due to its less resource-consuming method of doing full-screen antialiasing which only simulates super-sampling. The price of this tandem is much higher, too.
There is in fact no difference between the GeForce 7900 GT and GeForce 7800 GTX on the rather large-scale Pier map even when we compare the corresponding SLI configurations in extreme FSAA modes. The memory subsystem load must be not very high and it is the pixel processors that become a bottleneck here – and there is a mere 20MHz of difference between the GPU frequencies of the two graphics cards. The Radeon X1800 XT leaves no chance to the GeForce 7900 GT, but Nvidia doesn’t mean its $299 product to compete against this monster from ATI. The GeForce 7900 GT is indeed quite competitive against the slower Radeon X1800 XL.
We’ve got the same results on the Research map, but the Radeon X1800 XT doesn’t look as superior as it has been in the previous test, at least when we analyze its single-card performance.
The performance of the GeForce 7900 GT SLI is high enough for you to use SLI AA, but you’ll have to limit yourself to 1024x768 at 16x SLI AA. At 8x SLI AA, all the resolutions seem to be playable.
Far Cry ’s HDR support for ATI’s graphics cards isn’t yet optimized. That’s why the Radeon X1800 XT is far slower than the GeForce 7900 GT. The GeForce 7800 GTX 512 outperforms the GeForce 7900 GT SLI and GeForce 7800 GTX SLI and turns in the best result here.
This is true for both the demos we use in our tests. Note also the lower efficiency of SLI in comparison with CrossFire whose scalability is better in the HDR mode. In the HDR-less game mode, Nvidia’s multi-GPU technology works fine.
The single GeForce 7900 GT is a little behind the GeForce 7800 GTX 512 in high resolutions despite the tremendous difference in their clock rates and memory amount. It’s a rather strange thing since F.E.A.R. is known to require a lot of texture processing besides abounding in pixel shaders. As before, none of the single cards can offer you 60 frames per second in resolutions above 1024x768 with turned-on 4x FSAA and 16x anisotropic filtering.
The new card performs expectably in SLI mode: it is a leader when using 4x FSAA (in resolutions above 1024x768) or the more difficult 8x SLI AA. The difference between the two tandems from Nvidia is a mere 3-5fps. It’s no good making any comparisons in the 16x SLI AA mode because the GeForce 7900 SLI and Radeon X1800 XT CrossFire perform under different conditions and, moreover, are both too slow for comfortable play.
Half-Life 2 produces an already familiar picture; the GeForce 7900 GT is almost as fast as the GeForce 7800 GTX, and both the cards are successfully competing with the Radeon X1800 XL, but not with the more powerful Radeon X1800 XT.
The new graphics card does somewhat better in SLI mode, enjoying a 5-10% advantage over the GeForce 7800 GTX SLI. That’s not enough for a breakthrough to the next resolution, though: the frame rate is still only comfortable in 1280x1024 at 8x SLI AA 8x whereas the Radeon X1800 XT CrossFire easily yields over 80fps in 1600x1200.
And there’s nothing extraordinary again: the GeForce 7900 GT equals the GeForce 7800 GTX in all the modes, being a much more economical solution at that. The Radeon X1800 XT consumes even more power, but delivers nearly the same performance except for the 14x/16x FSAA mode where the Radeon X1800 XT CrossFire is victorious only thanks to its less resource-consuming implementation of 14x full-screen antialiasing.
CrossFire and SLI technologies still do not work in this game. Turning them on leads to a terrible performance hit.
Like in most other tests, the new graphics card is a little better than the GeForce 7800 GTX only when we use SLI AA; and the performance growth is smaller in higher resolutions. Meanwhile, the game runs at a high enough speed for you to play with enabled 8x SLI AA in 1280x1024 resolution – the frame rate is never lower than 60fps.
The player can also try the 16x SLI AA mode, although the average speed of the GeForce 7900 GT SLI and GeForce 7800 GTX SLI is much lower then. Anyway, the min speed of 40fps in 1280x1024 is quite a satisfactory result, considering the excellent antialiasing quality you have in this mode.
The new card enjoys a colossal advantage in speed here: up to 50% in 1600x1200 with enabled 8x SLI AA! This is not a testing error since we rechecked the results a few times. We can’t say why the GeForce 7900 GT SLI performs like than in Quake 4 . Perhaps we are dealing with some software optimizations of SLI technology here.
The speed growth is smaller in the 16x SLI AA mode: 20-22% in all the resolutions.
The GeForce 7900 GT is beaten by the Radeon X1800 XT despite its 24 TMUs and the fact that this 3D shooter uses shaders with multiple texture lookups (from 4 to 8 per shader). Why? Serious Sam 2 just needs 512 megabytes of graphics memory at its maximum graphics quality settings. Otherwise its speed gets much lower.
The GeForce 7900 GT has the lowest minimum speed among all the participating cards even in the lowest resolution. The game may slow down to 1-5fps on this card whereas the GeForce 7800 GTX, a card with similar characteristics, ensures a min speed of 12-26fps depending on the display resolution. It must be some problem in Nvidia’s driver because we reran this test to get the same picture of performance. We observed no image artifacts in this game, by the way.
The GeForce 7800 GTX 512 and Radeon X1800 XT are the only single-GPU solutions in this test session that allow playing Serious Sam 2 with turned-on 4x FSAA, but you are limited to 1024x768 resolution. The Radeon X1800 XT is just a little slower than the SLI configuration with two GeForce 7900 GT.
The performance of the tested multi-GPU solutions in the extreme antialiasing modes is too low for comfortable play.
This game was not tested in FSAA modes since HDR support is disabled even on ATI’s graphics cards then and the visuals quality degenerates greatly. It is also impossible to turn on the Bloom effect alongside with HDR. CrossFire technology support for TES IV is missing in the current version of the Catalyst driver. To enable it, you have to rename the file Oblivion.exe into AFR-FriendlyD3D.exe or you’ll get no performance boost. The game having no integrated benchmarking options, we had to measure the speed with the FRAPS utility. We tested each card two times to give you a fuller picture: in an open environment and in the Imperial City dungeon.
The Radeon X1800 XL is a little faster than the GeForce 7900 GT in low resolutions, but then slows down beginning from 1280x1024 resolution. We guess the main reason is its rather slow memory clocked at 500 (1000) MHz.
As for playability, the new card from Nvidia allows using 1024x768 at the max graphics quality settings. In a SLI configuration, it makes all the standard resolutions, including 1600x1200, playable, at least in closed environments and dungeons. Let’s see how it does in the open.
Unfortunately, the open spaces of TES: Oblivion are much harder for the graphics subsystem to process. Here, the GeForce 7900 GT SLI cannot give you more than 52fps in 1024x768. The single cards can do no better than 35-40fps. This doesn’t seem to be enough for comfortable play considering that Oblivion is technically a shooter with first-person view.
The GeForce 7900 GT, GeForce 7800 GTX and Radeon X1800 XL deliver the same performance here in all the resolutions. In a higher category, the GeForce 7800 GTX 512 rivals the Radeon X1800 XT. The single GeForce 7900 GT cannot cope with 1600x1200 resolution, but it is strong enough to ensure a comfortable frame rate in the other display modes.
The GeForce 7900 GT SLI platform is competitive against the Radeon X1800 XT CrossFire in 1024x768 only, yet this is still a great result for such a low-cost solution. It also ensures an excellent speed reserve in high resolutions, even though not as big as provided by the dual-GPU solution from ATI Technologies.
Quite expectedly the Radeon X1800 XT CrossFire wins the 8x FSAA + 16x AF mode. We probably should be comparing the GeForce 7900 GT SLI with a Radeon X1800 XL CrossFire system, but we don’t have two samples of the latter card as yet.
The new card from Nvidia performs superbly as a single card as well as a SLI couple. It wins all the modes and resolutions, expect for 1600x1200 in the 16x SLI AA mode where the SLI configuration with two GeForce 7900 GT is about 4-5% slower than the Radeon X1800 XT CrossFire. This is all quite expectable considering that the engine of this flight simulator is optimized for the special features of the GeForce 6/7 architecture.
X3: Reunion is a very demanding game, so you have to limit yourself to running it in 1024x768 on your GeForce 7900 GT. The same is true for the GeForce 7800 GTX and Radeon X1800 XL, though.
When using a SLI platform with two GeForce 7900 GT, you can choose any resolution you like with turned-on 4x FSAA or even 1024x768 with 8x SLI AA. That’s not bad for a tandem in which each card has an official price of only $299.
Note that the Radeon X1800 XT CrossFire is not far better than the single Radeon X1800 XT: CrossFire technology seems to work incorrectly yet in X3: Reunion.
This game works correctly with Super AA and SLI AA, but its speed varies rather too much. So we don’t publish the test results for such modes in order not to mislead you.
Boasting 24 pixel processors and 24 TMUs, the GeForce 7900 GT easily breaks away from the Radeon X1800 XT. The new graphics card from Nvidia enjoys a huge advantage of 50% in 1600x1200! The single GeForce 7900 GT looks good enough even when full-screen antialiasing is in use. We guess the average speed of 53fps in 1280x1024 is more than enough for playing a real-life strategy game with all possible comfort.
Like in many other games, the results of the GeForce 7900 GT and GeForce 7800 GTX almost coincide, just as the tech characteristics of these cards do. As usual, Dawn of War makes good use of the special features of the GeForce 7 architecture, namely of its 24 texture-mapping units and UltraShadow II technology. As a result, the new graphics card from Nvidia is successfully challenging the Radeon X1800 XT which is a higher-class product.
The new card is faster in multi-GPU mode than the GeForce 7800 GTX SLI configuration and is everywhere in the lead, except in the resolution of 1600x1200 at 16x SLI AA. The Radeon X1800 XT CrossFire follows it very closely, though. The performance of the multi-GPU systems is too low for comfortable play at the highest antialiasing level. In the easier 8x SLI AA mode the GeForce 7900 GT SLI runs the game at an acceptably high speed in 1280x1024.
We can’t see anything particularly interesting in Aquamark3 mainly because of the respectable age of the benchmark itself. We can see, however, that the GeForce 7900 GT and GeForce 7900 GTX are equals in this test at first, but then there’s a bigger gap between them in the 8x and 16x SLI AA modes. It’s also clear that the GeForce 7900 GT SLI cannot contend with the Radeon X1800 XT in these modes: in the first case due to its lower-performing memory subsystem (a lower frequency and a less efficient controller), and due to the sheer difficulty of performing 16x FSAA in the second case.
GeForce 7900 GT didn’t manage to outperform Radeon X1800 XT, which is quite logical, but it did leave Radeon X1800 XL far behind. Speaking about multi-GPU tandems, the SLI configuration built of two GeForce 7900 GT has certainly yielded to Radeon X1800 XT CrossFire, but the performance difference was less that 1000 points. It is a very good result, keeping in mind the difference in clock speeds, amount of onboard graphics memory, different price and power consumption of these two solutions.
In Game 1 test Radeon X1800 XT outpaces GeForce 7800 GTX and the new GeForce 7900 GT by about 10% in all resolutions. The corresponding multi-GPU configurations however yield quite noticeably to Radeon X1800 XT CrossFire only in 1600x1200, where work with the memory subsystem matters the most.
It is for exactly the same reason that Radeon X1800 XT CrossFire defeats GeForce 7900 GT SLI and GeForce 7800 GTX SLI in SLI AA/Super AA modes. Although here we have to point out that the performance difference is big enough only when we enabled SLI AA 16x/Super AA 14x. As you remember, ATI graphics cards find themselves in a more advantageous situation, because the anti-aliasing methods of the Super AA 14x mode eat up considerably less resources than those employed y Nvidia in SLI AA 16x mode.
Unlike Game 1 test, the second test from the 3DMark05 benchmarking suite doesn’t require very high fillrate. Therefore, Radeon X1800 XT gets much farther ahead of GeForce 7900 GT than in the previous case. As for the Radeon X1800 XL, our hero manages to compete against it quite successfully.
In test modes with extreme anti-aliasing involved, GeForce 7900 GT SLI also loses to Radeon X1800 XT CrossFire, and the performance difference appears even bigger than in the previous case. Namely, the performance difference can reach up to 15-25% with FSAA 8x enabled.
We see pretty much the same picture in game 3 test. However, since it requires high fillrate, Radeon X1800 XT doesn’t get too far ahead of GeForce 7900 GT and GeForce 7800 GTX, unlike the situation in Game 2 test.
All in all, the total score of our GeForce 7900 GT correlates very nicely with the results of each Game test separately, even though there was full-screen anti-aliasing mode actively used in the first case. GeForce 7900 GT failed to defeat Radeon X1800 XT, which wasn’t the goal anyway. At the same time it proved a worthy rival to Radeon X1800 XL.
The results of GeForce 7900 GT and Radeon X1800 XT are only 100 points apart. Taking into account the requirements 3DMark06 sets to the graphics subsystem, as well as the price and power consumption of Radeon X1800 XT, the obtained results are quite an achievement for the Nvidia GPU. When we talk about multi-GPU systems, the performance difference between GeForce 7900 GT SLI and Radeon X1800 XT CrossFire is slightly bigger and equals 186 points. Although, this is a total score diagram and it represents more or less generalized numbers, which do not illustrate the performance of our solutions in SM2.0 and SM3.0/HDR tests. Now let’s take a look at each test separately for more information.
GeForce 7900 GT is only 31 points behind Radeon X1800 XT. Its 24 texturing units make up for lower clock speed. The GeForce 7900 GT SLI configuration also proves quite successful here, as it is only 60 points behind Radeon X1800 XT CrossFire. Our hero owes this excellent result to the fact that Radeon X1800 XT cannot really benefit from its great ability to process complex v.3.0 shaders.
In SM3.0/HDR tests, the single GeForce 7900 GT loses to Radeon X1800 XT a little bit more: 62 points. It could be the relatively low fillrate of Radeon X1800 XT as well as the absence of Fetch4 function that determined these results. The latter function serves to speed up dynamic shadows processing through Cascade Shadow Maps used in 3DMark06.
Unlike the systems with single graphics cards, Radeon X1800 XT CrossFire manages to leave GeForce 7900 GT SLI farther behind: the gap makes over 200 points.
Since GeForce 7900 GT GPU cannot use full-screen anti-aliasing and HDR at the same time, we will only show the SM2.0 results that we have obtained in FSAA 4x + AF 16x mode. In more resource-hungry AA modes, the performance is so low that we cannot take the measurements correctly. Besides, we have also omitted the 1600x1200 resolution, because 3DMark requires 512MB of onboard graphics memory for the system to run with anti-aliasing enabled.
When we enabled FSAA and anisotropic filtering, GeForce 7900 GT could compete with Radeon X1800 XT on equal terms only in 1024x768. In 1280x1024 the memory subsystem performance turned into a bottleneck for the newcomer. And the overall good results in the first SM2.0 test can certainly be explained by the 24 TMUs it has.
The results of Game 2 test prove everything I have just said. This test is not so fillrate-hungry, so Radeon X1800 XT benefits a lot from its higher clock speed and its ability to process pixel shaders fast enough. It manages to get about 35% ahead of GeForce 7900 GT in 1280x1024, while in the previous test the performance difference was only 10%.
In this case the individual benchmark analysis doesn’t prove the total scores: GeForce 7900 GT yields to Radeon X1800 XT in both SM2.0 tests. However, we should remember that the results of individual tests have been obtained with enabled full-screen anti-aliasing, which uses a lot of the memory subsystem resources.
No doubt that the new Nvidia graphics card positioned for the $299 price segment is an extremely successful solution. GeForce 7900 GT inherited all the good features of the GeForce 7800 GTX, but at the same time turned out less complex, less expensive and much more economical thanks to the new G71 GPU.
The newcomer proved just great during our real-time test session. In most tasks it outperformed Radeon X1800 XL and in some of them it competed on equal terms with a more powerful Radeon X1800 XT. Of course, 24 TMUs it features helped a lot to achieve this success, because it resulted in higher fillrate – an important parameter for games rich in texturing samples. This feature combined with about 48W of power consumption (which is much lower than by GeForce 7800 GT and Radeon X1800 XL) and excellent overclocking potential give all every right to award GeForce 7900 GT with a title of the best $299 graphics card in the today’s market.
So, if Nvidia’s partners manage to establish regular large-quantity supplies of the new GeForce 7900 GT based products, a lot of users will most likely prefer the newcomers to the Radeon X1800 GTO and XL based solutions. And in some cases, they may even give up Radeon X1800 XT…