Quad SLI Vs. 3-Way SLI

Sometimes, less is more. Sadly, that may be the case for Quad SLI.

Nvidia launched its highly anticipated GeForce 9800 GX2 GPU model back in March, and many had high hopes for the technology. Designed to compete with ATI’s Radeon HD3870 X2, which put ATI’s CrossFire scheme on a single graphics card, Nvidia new product essentially combined two 8800 GTS GPUs on a single card. Therefore, two 9800 GX2 cards would give a system the long awaited and almost mythical power of Quad SLI – but for real this time.

Gamers and PC enthusiasts most likely recall Nvidia’s first endeavor with Quad SLI back in 2006. The graphics card company introduced the 7900 GX2, but considering the technology boasted four GPUs, the performance upgrade over traditional SLI or even a single GeForce 8800 series card was disappointingly minimal. At the time, much of the disappointment was attributed to limitations with Windows XP and as a result there was hope that Vista would be able to bring better performance out of a new Quad SLI series with proper scaling.

That day has arrived, but the results are once again not what many had expected, including us at Tom’s Hardware. We recently received another monster gaming rig from Falcon Northwest – a Mach V Quad SLI system, to be exact, that came with two Nvidia 9800 GX2 cards. Needless to say, we were eager to see how a Quad SLI system performed compared to a 3-way SLI scheme, which has produced somewhat mixed results since its debut.

quad sli falcon

We decided to match up the Mach V Quad SLI from Falcon Northwest against Puget’s Deluge 3-way SLI system (see next page for the systems’ specifications). In essence, the match-up compared the performance of two 9800 GX2 cards against three 8800 Ultra cards. While the Deluge L3 had a slight advantage with its CPU clock speed, the Mach V has four GPUs and twice as much memory. To properly set the stage for this comparison, it’s important to recap some previous results and findings.

quad sli falcon

First and foremost, Tom’s Hardware did an exhaustive review of the GeForce 9800 GX2 in March and found that it was one of the fastest, most impressive graphics cards currently on the market. Nvidia’s newest offering easily bested ATI’s rival dual-GPU card, the Radeon HD 3870 X2. However, our benchmark test results also showed that the 9800 GX2 only produced slim frame rate improvements over a single 8800 Ultra at the highest resolutions with anti-aliasing enabled. So despite being incredibly fast and better than ATI’s offering, the price-performance of the 9800 GX2 was disappointing.

quad sli falcon

Second, we’ve done extensive testing on a couple 3-way SLI systems at Tom’s Games in recent months, including a version of Falcon Northwest’s Mach V and the Deluge L3 from Puget. While 3-way SLI offered some impressive performance gains over traditional SLI, we saw some inconsistencies and anomalies that suggest the technology wasn’t quite optimized; on some games, the 3-way SLI systems posted outrageous frame rate increases, while on others the improvement was virtually non-existent. Complicating matters was the fact that 3-way SLI was having trouble handling Crysis at a 2560x1600 resolutions.

quad sli falcon

Therefore, questions loomed about how Quad SLI would perform considering 3-way SLI was still somewhat new and hadn’t achieved the kind of expected results. However, the 9800 GX2 has some tricks up its sleeve. For example, Nvidia has touted the dual-GPU engine’s 256 stream processors and 1 GB framebuffer, which the company claims will give a 30-50 percent faster performance than an 8800 Ultra. Nvidia also stated that the 9800 GX2 would have amazing scaling thanks to 4-way AFR (alternate framer rendering), which allows the four GPUs to work on their own separate frames rather than combining their power on a single task.

So how does Quad SLI stack up against 3-way SLI? Continue on to see the benchmark test settings and results.

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  • jonisginger
    Why not a test a game that isn't limited by CPU...like Cryshit
  • paradigital
    Care to actually explain why the FNW system got such low CPU utilisation on HD playback?
  • david__t
    It would be nice to see the HD resolutions listed regularly (1920 x 1080) as people with this much grunt are undoubtedly using their PCs on HD TVs @ 1080p. I mean who on earth plays at resolutions over 2000 pixels wide?
  • operation_turkey
    I'm amazed at the poor selction of games that they have chosen to benchmark on. I mean 3 old games and 2 very CPU bound games. I seriously have no idea what they where thinking. Nobody is every going to get a quad/tri SLI setup and then go and play serious sam 2. I really hope they redo this with some good benchmarks: 3DMark Vantage, Crysis, Company of Heroes: OF and maybe Oblivion and UT3.
  • rhaz
    omg...where's crysis, where's ut3...hell where is oblivion?! :O I thought this was supposed to be a thorough test, not just a means to show that quad-SLI performs less than 3-way SLI in SOME game titles...
  • Flakes
    i would like to comment, but i would just repeat whats already been said, this review gets two thumbs down.
  • WiredEvolution
    Worst review ever.
  • Anonymous
    Why did they test 3 ultra's against essentialy 4 8800GTS 512's. Also its not an equal test because the two system are different, they should have used the same mobo, processor, ram and hdd etc