by Alexey Stepin
12/28/2005 | 12:08 PM
UPDATE: We are working on the update to the article. We believe that performance anomalies have been caused by issues with the BIOS of the mainboard. Once the investigation is completed, the text will be revised and a notification will be posted.
NVIDIA Corp. released its scalable link interface (SLI) multi-GPU technology targeting extreme gamers back in 2004 in an attempt to regain high-end market share back from ATI Technologies. Along with the multi-GPU capability, NVIDIA has released its new breed of chipsets, the nForce4, one of which was specifically designed to support the reborn SLI multi-GPU technology.
A drawback of the original nForce 4 SLI chipset from NVIDIA was support for only reduced PCI Express speed from x16 to x8 in case of a multi-GPU setup. While it was clear that additional bandwidth would hardly improve performance in case of two GPUs, in the light of the fact that NVIDIA is mulling about quad-GPU setups a more advanced nForce4 SLI – the nForce4 SLI x16 has been developed.
The new core-logic provides two full-speed PCI Express x16 slots for graphics cards, which should potentially boost performance. But in case of AMD chipsets the company had to cut-down bandwidth for central processing unit, which may negatively affect performance. Whether it does, the review will explain.
ASUS usually packages its graphics cards into bright, gaudily-colored boxes, but mainboards are quite a different matter, especially top-end mainboards like the A8N32-SLI Deluxe model. The restrained colors and the lack of multicolored pictures create the image of a solid, reliable product – and the new mainboard from ASUS is exactly like that.
The new package design from ASUS uses only three colors besides the gray tones: bright orange, light green and yellow. The name of the series the A8N32-SLI Deluxe belongs to – AiLife – is in orange. The same color emphasizes the purpose of the product – “Gaming”. In the bottom right corner you can read some info about the technical characteristics of the mainboard and see a few logotypes (AMD, NVIDIA, and Corsair). You can flip back the front side of the packaging to learn some more information about the mainboard, including a detailed list of its characteristics:
The box that contains the mainboard and the accompanying accessories is dark, but the cardboard is glossy rather than matte. There’s nothing superfluous here, just the ASUS and AiLife logotypes and the name of the product. The A8N32-SLI Deluxe comes with the following accessories:
Although this is a Deluxe mainboard, its accessories are not exactly luxurious as opposed to the A8N-SLI Deluxe and Premium, but you do get everything necessary to use it. Take note that there is only one two-port USB 2.0 bracket included, so the user can only make use of six out of the ten USB 2.0 ports supported by the chipset unless there are extra ports on the system case.
The idea of a flexible universal SLI connector was long on the mind of enthusiasts of multi-GPU solutions, but all bridges supplied with mainboards were a solid textolite card with two connectors and its length was determined by the placement of the PCI Express x16 slots on the particular mainboard. If the MIO bridge was lost or damaged, the user found itself in a really big trouble. Although a flexible connector was rumored to be impossible, ASUS did make it. This connector can be used not only with the A8N32-SLI Deluxe, but also with any other SLI-compatible mainboard.
The small radial blower that is supposed to be installed on the heatsink of the power circuit’s load-bearing components deserves mentioning, too, but we are going to discuss it in more detail later on.
After we’ve given an appraising look to the package and accessories, it’s time to take the mainboard itself out of its antistatic pack for closer examination.
Unlike the earlier single-chip versions of the nForce4, the nForce 4 SLI X16 consists of two pieces, and the new mainboard is more densely populated than the A8N-SLI Deluxe or A8N-SLI Premium, the size of the PCB being the same. The number of expansion slots has been reduced from 7 to 6, and the new mainboard carries two PCI Express x16 slots, one PCI Express x4 slot, and three PCI slots. Since the new chipset provides 16 PCI Express lanes to each of the graphical slots, the ASUS A8N32-SLI Deluxe carries no logic to configure them – it has become unnecessary. The slots are placed conveniently enough, considering that the designers had little elbowroom. If you install two graphics cards with single-slot coolers, all the three PCI slots are ready to take in your expansion cards, but if you’ve got two ASUS Extreme N7800GTX TOP, for example, you’ll have only one accessible PCI slot. On the other hand, this Deluxe mainboard features extended functionality, so there’s little need to install any expansion cards. And even in the worst case you’ll have one PCI slot you can plug a TV-tuner or a standalone audio card into. Do not also forget about the PCI Express x4 slot – such peripherals are steadily gaining in popularity.
The CPU socket is shifted a little downwards because the mainboard employs a sturdy eight-channel power circuit and some of its load-bearing elements are located along the top edge of the PCB. Unfortunately, the heat pipes of the chipset’s cooler are so close to the fastening frame that you may find it difficult to install some CPU coolers. The power connectors are placed properly and the power cables won’t hinder normal operation of the CPU cooler. The second Parallel ATA slot is difficult to access, but it is rather seldom used in modern computer systems anyway. A 4-pin Molex connector marked as EZ_Plug supplies additional power to the PCI Express x16 slots in case you install two graphics cards that don’t have an additional power connector, for example GeForce 6600 GT.
The DIMM slots are placed properly. They are above the top PCI Express slot and a long graphics card won’t block the latches. There’s also a small gap between the slots of each channel so that memory modules with massive heat-spreaders could be easily installed. As usual, the connectors of the first memory channel are painted blue so that you plugged your memory in correctly.
You are unlikely to encounter any problems when you’re assembling a computer around this mainboard. The heat pipes may only become an obstacle during installation of certain CPU coolers. Some problems may also arise if you need to reset the BIOS settings since the appropriate jumper is located right under the latch of the bottom PCI Express x16 slot and is hard to access even if the slot is free. If the slot is occupied, the jumper is altogether inaccessible. And still, designing such a complex mainboard as A8N32-SLI is a daunting task, and we think the people at ASUS did a good job of it.
The disk subsystem of a computer based around the ASUS A8N32-SLI Deluxe would have six Serial ATA-II ports, four of which are provided by the controller integrated in the South Bridge and two more are provided by an onboard Silicon Image SiI3232 controller. One of the latter two ports is located on the mainboard’s I/O panel and allows connecting an additional hard drive without opening the system case (of course, if the external HDD has a power source). The Serial ATA-II specification describes this hot-swap feature under the name of “SATA On-the-Go” and it may come in very handy in some situations.
This external Serial ATA connector explains the strange position of the onboard controller – it is usually installed closer to the bottom right corner of the PCB. As for RAID functionality, the integrated disk controller from the nForce4 chipset supports RAID 0, 1, 0+1, 5, 10 and JBOD, while the dual-port SiI3132 chip supports only RAID 0 and 1. We think the total of six Serial ATA-II ports is going to satisfy most users.
The Parallel ATA connectors are placed in an odd way. The first channel is oriented along the PCB’s length, while the second one is placed as usual. You may find it difficult to access the second connector as it is right next to the 24-pin power connector, but we don’t consider this as a serious defect because hard drives with the Serial ATA interface are more popular today, while the Parallel ATA interface is mostly employed for optical drives, for which one channel should be enough.
The mainboard’s networking section is represented by two chips from Marvell, one of which is a physical-level interface (Alaska 88E1111) for the NVIDIA Gigabit Ethernet controller integrated into the chipset. The other chip, Marvell Yukon 88E8053, is a full-fledged one-chip Gigabit Ethernet controller that connected across a PCI Express x1 bus. Of course, NVIDIA’s integrated controller supports the exclusive hardware firewall ActiveArmor. Both the networking controllers support AI NET technology that helps diagnose network cables and locate damaged sections. The Wireless Edition of the ASUS A8N32-SLI Deluxe also carries an 802.11b/g wireless controller, which is missing on our sample.
The nForce 4 SLI X16 still does not support the High-Definition Audio standard (also known as Azalia), so the mainboard’s audio section consists of an eight-channel AC’97 codec Realtek ALC850. It’s going to be enough for all users except for audiophiles who will probably install a standalone audio card with I2C codecs and 24-bit audio support, anyway. As usual, the mainboard’s audio headers can be connected to the system case’s audio ports.
NVIDIA’s chipsets do not support the FireWire interface, but the A8N32-SLI Deluxe is equipped with a Texas Instruments TSB43AD22A controller that offers you two IEEE1394a ports. The USB 2.0 interface is implemented through the nForce4 – its 10 ports are more than sufficient for today.
As for legacy ports, the mainboard has an LPT connector in its traditional place. The customary position of the COM ports is occupied by an optical and coaxial S/PDIF connectors and an external Serial ATA-II port, but one COM port can still be enabled through the appropriate bracket for the back panel of the system case. You can also find a Game port on the bracket with two SUB 2.0 ports, so you will be able to connect your old joystick to this mainboard.
The first revision of the ASUS A8N-SLI Deluxe was justly criticized for being very noisy – the chipset was cooled with a fan that was rotating at about 8000rpm! Despite its tiny size, the fan was a real torture to sensitive ears as its noise was mostly in high-frequency range. Ironically enough, the chipset was still cooled rather poorly due to the non-optimal design of the heatsink. In the A8N-SLI Premium the fan was replaced with another model with better noise characteristics.
And later on ASUS decided to abandon active cooling altogether and developed the noiseless cooler AI Cool-Pipe. This cooler has been further developed for the A8N32-SLI Deluxe as this mainboard needs cooling for both pieces of the chipset. It now consists of two heat pipes. One pipe cools the South Bridge and, partially, the North Bridge as it transits through its heatsink. The second and shorter pipe is mostly busy cooling the North Bridge.
The pipes transfer heat to a small copper heatsink installed to the left of the CPU socket – it also cools some transistors in the power circuit. It may seem that exhausting the hot air from this area through the back panel would be the optimal solution, as is implemented on some mainboards from ABIT and EPoX, but ASUS thinks different. The heatsink is supposed to be cooled by the air stream from the CPU cooler. This is a solution, too, although we think that pumping the hot air to the outside would still have been better. The mainboard uses an 8-channel power circuit with a number of power transistors, some of which are placed above the CPU socket. These transistors are cooled with a small aluminum heatsink like the one installed on the ASUS A8N-SLI Deluxe.
So again, the mainboard doesn’t exhaust hot air through the system case’s back panel and it means that if you install a water-cooling system, the chipset and the power circuit may overheat because the CPU water-block wouldn’t create airflow to cool the heatsinks. In this case, you must install the special blower included with the mainboard. Of course, you have to sacrifice the mainboard’s noiselessness, but you will at least be sure that the mainboard won’t fail due to overheat of the chipset and/or power transistors. You shouldn’t worry about the second heatsink – the power supply’s fan is going to cool it all right in every case.
The mainboard has six standard 3-pin fan connectors one of which is going to be occupied by the CPU cooler if you use an air-cooling solution and the same five connectors will be available to you if you’ve installed a water-cooling system. This should be more than enough for 99% of users. The mainboard can keep track of the speed of three fans: CPU_FAN, CHA_FAN1 and RWR_FAN. The CPU_FAN connector can be additionally managed by the Q-FAN feature which adjusts the CPU cooler speed depending on the CPU temperature.
Like all mainboards from ASUS, the A8N32-SLI Deluxe uses the AMI BIOS. The product is targeted at PC enthusiasts in the first place, so we’ve got plenty of settings here.
Almost any thing can be adjusted, although the adjustment of the voltage on the chipset’s North and South bridges is limited to adding 0.2V to the default value. Meanwhile, the voltage on the memory slots can be varied from 2.60 to 3.20V and the CPU voltage from 1.0 to 1.7625V. The CPU frequency multiplier can be adjusted from 4x to 25x. The PCI bus frequency is fixed at 33MHz, while the frequency of the PCI Express bus can be varied from 100 to 200MHz stepping 1MHz. The HyperTransport frequency range is very wide, but setting it to above 1000MHz makes the system hang up. This is probably some kind of reserve for the future, for upcoming cores from AMD, but so far these high frequencies are practically useless.
The number of memory subsystem settings is astonishing – you can adjust almost every parameter imaginable. CAS Latency can be set at 1.5 to improve a little the performance of PC2700, but this mode is rather too aggressive for PC3200 modules. The memory frequency range is 100-250MHz. Since AMD’s CPUs have an integrated memory controller, you can use frequencies above 200MHz only with revision E cores that support DDR500 SDRAM (see our article called AMD Athlon 64 Processors on E Core: Memory Controller Peculiarities in Detail ).
We have only one complaint about the Power page – it shows the speeds of only three fans, including the CPU cooler’s. Otherwise, the options are typical enough. Note that you can turn on ASUS Q-FAN technology from here.
The BIOS of the A8N32-SLI Deluxe allows you to change the logotype displayed at the start of the system with a custom image (MyLogo2 technology) and also supports Crashfree BIOS 2 technology whose point is to restore the contents of a corrupted BIOS chip by means of a special image from a CD or diskette. This solution is much simpler than the additional chip other mainboard makers use as it doesn’t require hardware modification of the mainboard, but it won’t help if the BIOS chip is physically damaged.
Since our goal was to check if the new nForce SLI x16 chipset has any advantage over the ordinary nForce4 SLI, we used the same hardware parts with two different mainboards:
Two NVIDIA GeForce 7800 GTX graphics cards working in SLI mode constituted the graphics subsystem for the gaming tests. This will show if the two PCI Express x16 channels give any performance gain in games as opposed to the ordinary nForce 4 SLI config in which each x16 slot has only 8 PCI Express lanes. To avoid CPU-imposed limitations, we didn’t test 1024x768 resolution, but tested the popular 1280x1024 mode and the difficult but standard 1600x1200 resolution. We also didn’t test the systems in the “pure speed” mode, but added two new modes to our traditional “eye candy” settings (4x FSAA + 16x anisotropic filtering): 8x FSAA + 16x AF and 16x FSAA + 16x AF. The ForceWare driver was set up as usual:
We select the highest graphics quality settings in each game. If possible, we use the games’ integrated benchmarking tools and if not, we measure the frame rate with the FRAPS utility. We measure minimal as well as average fps rates whenever possible.
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 ForceWare driver as we also did for the higher levels of full-screen antialiasing.
These games and applications were used as benchmarks:
First-Person 3D Shooters
Third-Person 3D Shooters
Besides these gaming tests we also made use of WinRAR 3.51, Futuremark 3DMark2001 SE (build 330), Futuremark PCMark05 (build 110) and our own utility to test the bandwidth of AGP and PCI Express buses. For these tests the testbed included but one GeForce 7800 GTX graphics card. We offer you the results of the theoretical tests first as they are indicative of what you may expect from the ASUS A8N32-SLI Deluxe and the new chipset in real gaming applications.
The difference between the overall performance scores of the two platforms based on the two different mainboards is a mere 81 points or less than 2%. Alas, the difference is not in favor of the new mainboard from ASUS and the nForce 4 SLI X16 chipset.
If we put aside the architectural deficiencies of the new chipset, particularly the narrow HyperTransport channels between the CPU and the North Bridge, some imperfections in the BIOS and the overall mainboard design may account for that. We can recall our testing the early implementations of NVIDIA’s SLI platform in silicon when we also met a number of problems that were later successfully solved as the platform matured. Let’s take a look at the results of CPU and Memory tests – will they give us an answer?
The diagram shows that the performance of the CPU on the A8N-SLI Premium and the A8N32-SLI Deluxe mainboards is absolutely the same and the difference of 12 points is most likely due to a measurement error. We suppose that the test doesn’t load the CPU-chipset line very heavily and the narrowness of the appropriate HyperTransport channels in the nForce4 SLI X16 chipset doesn’t show up.
All modern processors from AMD come with an integrated memory controller, so the results are quite natural, even though the ASUS A8N32-SLI Deluxe scores 51 points less than the older mainboard.
The ASUS A8N32-SLI Deluxe is quite distinctly slower than the A8N-SLI Premium. The difference of 508 points can’t be regarded as a measurement error. So this is the first time the new chipset from NVIDIA meant to build a SLI platform with two full-width PCI Express x16 slots performs considerably slower than the older version of the chipset which only provides 8 PCI Express lanes per each graphical slot.
The newest version of Futuremark’s benchmarking suite runs at the same speed on both mainboards because the graphics subsystem performance is the main speed-limiting factor here. The main architectural deficiency of the nForce4 SLI X16 is not so conspicuous, even though the ASUS A8N32-SLI Deluxe is formally slower than the A8N-SLI Premium.
The CPU performance test from 3DMark05 makes it clear that the ASUS A8N32-SLI Deluxe is the slower of the two mainboards. In this test the central processor has to process some vertex shaders and to calculate the flight trajectory of the airship. The amount of data transferred between the central processor and the graphics subsystem is probably so large that the narrowness of the HyperTransport bus between the CPU and the chipset begins to affect the performance of the system, even though slightly. This is about the same thing that we can expect to happen in older games that do not use shaders, e.g. in Unreal Tournament 2004 . You’ll see the results of our gaming tests shortly while next go WinRAR and PCI Express Test.
The system bus – HyperTransport plays this role on the AMD64 platform – is loaded fully during a data-compression task, so it is natural that the ASUS A8N32-SLI Deluxe is slower than the A8N-SLI Premium. The gap isn’t bigger than 10%, but it’s a fact that the narrower HyperTransport bus connecting the CPU and the chipset has a negative effect on the performance of the nForce4 SLI X16.
The problem shows up more clearly in the PCI Express bandwidth test. The point of this test is in sending a certain amount of data from the system to the graphics memory and back again, the size of the transferred block varying from 64KB to 4MB. The utility makes use of the memory controller as well as the graphics bus and the bus that connects the CPU and the chipset (in this case it is the HyperTransport link). Here are the results the test produced on the nForce4 SLI and nForce4 SLI X16 platforms:
The mainboards do not differ much when the data block size is the smallest, although the ASUS A8N-SLI Premium is ahead of the ASUS A8N32-SLI Deluxe even in this case. The negative effect of the 8-bit HyperTransport channels between the CPU and the nForce4 SLI X16 North Bridge is concealed by various time latencies. At the biggest data block size this loss is minimal, so the architectural deficiency of NVIDIA’s new chipset shows up in full. The ordinary nForce4 SLI connected to the central processor via two 16-bit HyperTransport channels is 20% faster than the nForce4 SLI X16!
It’s the same when the data is transferred in the opposite direction, i.e. from the graphics card’s onboard memory into the system memory, except that the mainboards have nearly the same performance on smaller data blocks.
Our theoretical tests have showed that the new chipset from NVIDIA and the A8N32-SLI Deluxe mainboard based on it do not have any advantages over the older nForce4 SLI-based platform. In some cases, when there are large amounts of data traveling from the chipset to the CPU and back, the new mainboard is even slower than the older one because its HyperTransport bus between the CPU and chipset is two times narrower.
We want to remind you that the ordinary nForce4 SLI uses two 16-bit channels with a bandwidth of 8GB/s to either side while the nForce4 SLI X16 has two 8-bit, 4GB/s channels and the total bandwidth is 8GB/s against the nForce4 SLI’s 16GB/s. This design difference didn’t show up much in the theoretical tests, though. Will this be so in gaming applications, too?
We could not test Battlefield 2 on the new platform as the game was unstable and even refused to start in SLI mode. The other games worked normally, so the overall stability of the ASUS A8N32-SLI Deluxe is high.
While there is some difference between the mainboards on the nForce4 SLI and the nForce4 SLI X16 in the less difficult FSAA modes (and the difference is not in the favor of the latter), the gap vanished completely as soon as we turn on 6x and 16x antialiasing. Obviously, the two full-width PCI Express x16 slots constitute no advantage for this game. Note also that comfortable play is quite possible in 1280x1024 resolution with turned-on 8x FSAA.
The ASUS A8N32-SLI Deluxe is 1fps ahead of the older mainboard only when we use 8x FSAA in 1600x1200 resolution. This advantage amounts to less than 5% and it is probably due to measurement error rather than to any benefits from the newer chipset.
The new chipset is nowhere better than the older one. Moreover, the ASUS A8N32-SLI Deluxe is on average a little slower than the mainboard on the single-chip nForce4 that gives but 8 PCI Express lanes to each graphical slot. So the PCI Express x8 bandwidth is not a bottleneck in today’s applications even if you use extremely high antialiasing levels. Note also that the SLI config on two GeForce 7800 GTX ensures a playable frame rate in Far Cry even at 8x FSAA. This gives you a much higher visuals quality than with traditional 4x FSAA, especially if you also turn on the transparency super-sampling feature.
The A8N32-SLI Deluxe is still a little bit slower than the A8N-SLI Premium on this map, too, although the difference is never bigger than 3 frames per second. As for the absolute level of performance, it seems you can even turn on 16x FSAA in 1280x1024 resolution, but the speed reserve is going to be rather low – it may bottom out to below playable in the hardest scenes.
F.E.A.R. is a very demanding application, yet the combined power of two GeForce 7800 GTX ensures a frame rate of 60-65fps in 1280x1024 with enabled 8x antialiasing.
This 3D shooter brings just another disappointment. Either the 16 PCI Express lanes are enough for two graphics cards working in SLI mode or the insufficient bandwidth of the HyperTransport bus that connects the CPU and chipset is the limiting factor that negates the advantages of the new chipset. Once again, both HyperTransport channels that connect the CPU and the chipset are 8 bits wide, while the HyperTransport bus that connects the chipset’s Bridges is made of full-size 16-bit channels.
Half-Life 2 also seems indifferent to the number of PCI Express lanes the graphics cards are connected across. The game is so undemanding that the owner of two GeForce 7800 GTX can enjoy an unprecedented-quality 16x-antialised picture in it.
It’s all roughly the same on the d3_c17_02 map – the ASUS A8N32-SLI Deluxe is even a little behind the A8N-SLI Premium. So the standard SLI configuration, PCI Express x8 + x8, certainly provides enough bandwidth for current applications. But maybe the PCI Express x16 + x16 formula can give us a performance gain in some other game?
There is no big difference between the two mainboards in Quake 4 , either, even though it is a recently released title. Theoretically speaking, the graphics subsystem with two GeForce 7800 GTX allows turning on even 16x full-screen antialiasing, but you may want to limit yourself to 8x FSAA to play in 1600x1200 resolution.
This is such a demanding game that even the SLI configuration with two GeForce 7800 GTX gives you only about 50fps in 4x FSAA + 16x AF mode. If full-screen antialiasing of a higher level is turned on, the frame rate sinks below comfortable. As for the standings of the two platforms, we can’t see any difference between the nForce4 SLI and the nForce4 SLI X16 here just like we couldn’t in the tests above.
Unreal Tournament 2004 is the first game where the ASUS A8N32-SLI Deluxe is considerably slower than the older mainboard. The difference is most notable at 8x FSAA where it amounts to almost 10%. This is not such a big deal, but it shows that the nForce4 SLI X16 concept is not perfect. The reduced bandwidth of the CPU-chipset thoroughfare negates the potential benefits from the two full-fledged PCI Express x16 slots. This doesn’t show up much in games, but in CPU-intensive tasks, for example data compression, the new chipset may be much slower than the older one. The big gap between the nForce4 SLI and nForce 4 SLI X16 in Unreal Tournament 2004 is probably due to the fact that the game doesn’t use pixel shaders and puts but a small load on the graphics processor, so the performance of the graphics subsystem is not a performance-limiting factor here.
The ASUS A8N32-SLI Deluxe is slower than the A8N-SLI Premium in all resolutions on the Metallurgy map, too. Being not a very difficult game, Unreal Tournament 2004 allows using 16x FSAA on a SLI-compatible graphics subsystem consisting of two GeForce 7800 GTX cards.
This game is hard and beautiful, especially if the graphics card supports Shader Model 3.0. However, it doesn’t run any faster on the mainboard that provides 16 PCI Express lanes for each of the SLI-connected graphics cards. Note also that the performance is the same in 8x FSAA and 16x FSAA modes. We suppose that 256 megabytes of graphics memory is just not enough to turn on 16x antialiasing in this game, but unfortunately we don’t yet have two samples of GeForce 7800 GTX 512 to prove this supposition.
The difference between the two platforms is negligibly small even in the hardest video modes. The game is not graphically complex, so it is quite possible to turn on extreme full-screen antialiasing modes in it, although 16x FSAA would be rather too much, especially if you want to play in a high resolution.
The flight simulator Pacific Fighters doesn’t seem to notice any difference between the A8N32-SLI Deluxe and the A8N-SLI Premium. The results of the two platforms coincide to 0.1fps.
8x FSAA and 16x FSAA are unavailable even for owners of two GeForce 7800 GTX cards. And again, the performance of the SLI graphics subsystem does not depend on the number of PCI Express lanes attached to the graphical slots – 8 lanes is quite sufficient and more lanes just give no real performance gain.
The same is true for the other strategy game we use in our reviews, Warhammer 40000: Dawn of War .
The two nForce4 SLI-based platforms have similar speeds here, yet the newer chipset is a tiny bit slower.
The first test being rather simple and shader-less, the difference between the nForce4 SLI and nForce4 SLI X16-based platforms is as clear as in Unreal Tournament 2004 , and the newer chipset is on the losing side again.
The second test uses pixel shaders and the platforms both deliver the same speed here.
The third test is more geometrically complex than the second one, but the doubling of the number of the PCI Express lanes attached to the graphical slots doesn’t bring any tangible gains to the system based around the nForce SLI X16.
The fourth test agrees with the earlier ones that the new A8N32-SLI Deluxe has no advantages over the older A8N-SLI Premium mainboard.
The two platforms differ by less than 1 frame per second, which is in fact smaller than the measurement error range.
The second test from the 3DMark05 suite brings the same results.
And the third test confirms once again that having two full-width PCI Express x16 slots has no effect on the performance of the SLI-compatible graphics subsystem. This is at least true for the nForce4 SLI X16 chipset that communicates with the CPU across 8-bit HyperTransport channels.
We have tested the new SLI-compatible platform from NVIDIA based on the nForce4 SLI X16 chipset. The chipset provides two full-width PCI Express x16 slots and was expected to increase the efficiency of the SLI technology which had been previously limited to PCI Express x8 + x8 configuration. However, we could not see any significant performance gain in any of the games we checked the new platform in.
The results suggest that today’s games do not transfer so much data across the PCI Express x16 interface that the increased number of PCI Express lanes gave any effect for a SLI graphics subsystem. The PCI Express x16 + x16 formula is excessive today and, moreover, the performance of the new chipset was lower than that of the ASUS A8N-SLI Premium mainboard which is based on the older chipset!
The explanation of the newer platform being slower comes from one architectural feature of the nForce4 SLI X16. To ensure high-speed communication between the chipset’s North and South bridges, NVIDIA had to reduce the width of the HyperTransport bus the chipset connects to the CPU with and to use two 8-bit channels instead of the ordinary nForce4’s two 16-bit channels there. The smaller bandwidth of the CPU-chipset link does not show up in games, but the performance of applications that actively use the system bus, like data archiving utilities for example, may suffer a lot. We are not even sure the nForce4 SLI X16 will offer any advantage in the next generation of PC games, despite its two full-width PCI Express x16 slots, because the narrow HyperTransport bus will probable be a bottleneck. Being the first chipset with the PCI Express x16 + x16 formula, the NVIDIA nForce4 SLI X16 is interesting and unique, but it is no better than the ordinary nForce4 SLI, at least in current applications.
As for the particular implementation of the platform, the ASUS A8N32-SLI Deluxe is a superb mainboard, free from any obvious drawbacks. Our only gripe is about the accessories which might be more generous for a “Deluxe” model. The heat pipes may also make it difficult to install certain CPU coolers, but the total noiselessness of the mainboard’s cooling system makes up for this inconvenience. Generally speaking, it is a real trouble to design a SLI-supporting mainboard, especially based on a two-piece chipset, and ASUS did it just right. We think the ASUS A8N32-SLI Deluxe is currently the best foundation for a top-end SLI-compatible computer with an AMD Athlon 64 processor. And if you are into Intel’s processors, there also exists the P5N32-SLI Deluxe version on the nForce4 SLI X16 Intel Edition chipset.