NVIDIA's 3-way SLI: Can we finally play Crysis?
by Anand Lal Shimpi on December 17, 2007 3:00 PM EST- Posted in
- GPUs
Quad SLI Redux?
With the hardware requirements met, it's time to look at the software requirements. Currently, 3-way SLI is only supported under Windows Vista, not XP. Other than the OS stipulation, 3-way SLI isn't really any different from conventional 2-card SLI. Many of you will remember the ill fated Quad SLI product NVIDIA brought to market just under two years ago.
Quad SLI had three major problems that kept it from being a worthwhile product:
1) It relied on the 7950 GX2, which was a single card, dual GPU solution. The problem is that the each GPU on a 7950 GX2 was slower than a 7900 GTX. So a single 7950 GX2 was slower than a pair of 7900 GTXs. Quad SLI used two of these 7950 GX2s, so the performance improvement over a pair of 7900 GTXs wasn't all that great at its best.
2) The best performing games with Quad SLI used AFR (Alternate Frame Rendering) to divide up the rendering workload, where each GPU was responsible for rendering its own frame. The result is that GPU 1 would render frame 1, while GPU 2 would work on the next frame, GPU 3 would work on the third and GPU 4 would work on the fourth. DirectX 9 unfortunately only allowed for a 3-frame render ahead, meaning that this AFR mode wouldn't work. With the vast majority of games being DX titles, this posed a significant problem to Quad SLI performance.
3) The final issue with Quad SLI was that by the end of the year, G80 was out, and G80 was much faster. A pair of 8800 GTXs demolished a Quad SLI setup, and in some cases even a single card was faster.
Thankfully, 3-way SLI doesn't have these problems. The three-card SLI setup relies on regular 8800 GTX/Ultra cards, which are still among the fastest GPUs that NVIDIA offers today. The 3-frame render ahead limitations of DX9 aren't present in DX10, so we can get good scaling with AFR in DX10 titles.
The problem of planned obsolesce is a concern though and it's almost inevitable that 3-way SLI based on G80 will be replaced very soon. There's no doubt that NVIDIA will eventually replace the 8800 GTX and Ultra with G92 based variants, which will reduce power consumption and improve performance. The fact that G80 came out over a year ago should preclude any thoughts of purchasing a brand new 3-way SLI setup, but for users who already have two 8800 GTX or Ultra cards, adding a third is a mostly reasonable proposition.
The Test
Special thanks to both EVGA and ASUS for providing us with hardware for this review. Both EVGA and ASUS sent us 8800 Ultras and 780i based motherboards for this comparison, although it is worth mentioning that you could use a 680i motherboard and any brand (or mixture of brands) of 8800 GTX/Ultra cards - provide of course that your 680i motherboard has the necessary x16 PCIe slots.
| Test Setup | |
| CPU | Intel Core 2 Extreme QX9650 @ 3.33GHz |
| Motherboard | EVGA nForce 780i SLI |
| Video Cards | NVIDIA GeForce 8800 Ultra x 3 |
| Video Drivers | NVIDIA: 169.18 |
| Hard Drive | Seagate 7200.9 300GB 8MB 7200RPM |
| RAM | 4x1GB Corsair XMS2 DDR2-800 4-4-4-12 |
| Operating System | Windows Vista Ultimate 32-bit |
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kilkennycat - Tuesday, December 18, 2007 - link
...it's far more likely to be used by a (nV) video card functioning as a GPGPU for either gaming --- or in the short-term --- professional desktop applications. nV is making great strides in the professional scientific number-crunching and signal-processing communities with their CUDA toolset running on their current GPU offerings. They currently own ~ 86% of the "workstation graphics" market, but in a rapidly-increasing number of cases, graphics is not the sole function of the current nV workstation hardware. Wait for nVidia's next generation silicon and driver software which will be far more focussed on seamlessly merging GPU and GPGPU functionality. Also, wait for their true next-gen motherboard chip-set and not the cobbled-together "780i" which will implement symmetrical PCIe2.0 on all 3 PCIe x16 slots. Arriving about the same time as their next gen GPU family. Mid-2008 would be my guess.aguilpa1 - Tuesday, December 18, 2007 - link
Funny how your review doesn't address this blatant issue. yes it will run tri sli but don't expect it to do with the same Yorkfield used on the test board they used. Engineering samples of the QX9650 ran fine on the 680i SLI's but were changed with the retail versions. Whether it was Intels pissy way of getting back at Nvidia for not licensing SLI to them or Nvidia's way of making a buck off of selling an almost already obsolete board (nehalems coming next year). At this stage...who cares.ilovemaja - Tuesday, December 18, 2007 - link
that quote: His response? "JESUS". "No", I said, "not even Jesus needs this much power".Is one of the funnyest things i heard in my live.
Thanks for another good article, you are the best.
acejj26 - Tuesday, December 18, 2007 - link
In Crysis, you say that the third card offers a 7% performance boost over the 2 card configuration, however, it is only offering 1 fps more, which is just about 2%. Those numbers should be changed.Sunrise089 - Tuesday, December 18, 2007 - link
Not complaining, but I've noticed the last several GPU articles have been written by Anand, which isn't his normal gig. On top of that we get a reference to another GPU editor from back in the day. What's up?compy386 - Tuesday, December 18, 2007 - link
I'd be interesting to do a comparision between SLI and Crossfire once AMD gets some drivers out that actually support quad SLI. I saw a board on newegg that looks like I'd fit 3 3870s as well.AcydRaine - Tuesday, December 18, 2007 - link
AMD doesn't support "Quad-SLI" at all. There are a few boards on Newegg that will fit 4x3780s. Not just 3.compy386 - Tuesday, December 18, 2007 - link
The 3870s take up 2 slots so I only see boards that fit 3. Most of the boards will take 4 3850s though. Again, I'd like to see the performance number comparisons for scaling purposes.compy386 - Tuesday, December 18, 2007 - link
The 3870s take up 2 slots so I only see boards that fit 3. Most of the boards will take 4 3850s though. Again, I'd like to see the performance number comparisons for scaling purposes.SoBizarre - Tuesday, December 18, 2007 - link
Well, I’m glad to see this evaluation of 3-way SLI. It just gave me an idea about overcoming performance issues in games like Crysis. There is no need for building ridiculously expensive machines which draws insane amount of power. I have a better solution (although it won’t work for all of you). I’m just not going to buy a game which I can’t play in its full galore on decent system, at mainstream resolution (1680x1050).I don’t expect the latest and greatest, “show off” kind of a game to be playable at 2560x1600 with highest settings, full AA and AF. Not on a system with Q6600 and single 8800GT. But if you can’t do it on a system like one used by Anand here? Well, then it’s becoming ridiculous.
I’m trying to imagine a proud owner of machine with QX9650 @ 3.33GHz, 3 (that’s THREE) 8800 Ultras and shiny 30-inch monitor, not being able to play a game he just bought. What would be his thoughts about developer of that game? I guess not the pretty ones…