NVIDIA SLI Performance Preview with MSI's nForce4 SLI Motherboard
by Anand Lal Shimpi on October 29, 2004 5:06 AM EST- Posted in
- GPUs
Final Words
The performance advantages due to SLI are nothing to be disappointed with, using two GPUs NVIDIA is able to deliver next-generation graphics performance with today's cards. Keep in mind that our numbers were taken at relatively high resolutions with 4X AA enabled; without AA enabled and at lower resolutions the performance gains from SLI become much lower as you are far more CPU bound.
The GeForce 6600GT is the prime candidate for the SLI poster child as it is the most affordable card with SLI support from NVIDIA. Unfortunately our tests here today are more geared towards the higher end cards as the 6600GT, even in SLI mode, is still generally outperformed by a single 6800GT. At lower resolutions or with AA disabled, the performance of two 6600GTs would definitely be more similar to that of a single 6800GT. But the important thing to keep in mind here isn't what you can do with two cheaper cards and SLI, but rather the upgrade potential SLI offers. Buying a $200 6600GT today and upgrading to another one several months down the road, at a potentially much lower price, is a great way of getting the performance you want today while at the same time having a cheap upgrade path for when tomorrow's games come out.
The GeForce 6800GT in SLI mode truly skyrocketed to a new level of performance, but a very costly one. With a pair of 6800GTs selling for about the price of most users' upgrade budgets, we once again see more potential in the upgrade value of SLI rather than the initial purchase value. However, if you can afford it, a pair of 6800GTs in SLI mode will definitely offer some serious performance in all of today's games. Interestingly enough, spending close to $1000 on graphics cards still won't let you play at 1600 x 1200 with 4X AA at over 100 fps in Doom 3; but if you're willing to settle, over 60 fps is a piece of cake.
Although motherboard and graphics support for SLI is definitely close to being ready, we are not so certain about the maturity of the drivers. NVIDIA's own tests were conducted under three applications: Doom 3, Halo and 3dmark 05. Although our own tests added two more benchmarks, they didn't run without their fair share of display issues. The complexity of the SLI driver and ensuring game compatibility is undoubtedly a major factor in the release date of SLI. We are also hearing that chipset availability is a bit on the limited side for nForce4 SLI, with most manufacturers planning on shipping boards in early 2005. ASUS and MSI both seem to be on track to a release by the end of 2004, which will definitely give them the lead if NVIDIA can get finalized drivers out in time.
All is not quiet on the ATI front though, rumor has it that they are also planning on some SLI-like solutions on both the chipset and GPU side. Given the flexibility of PCI Express to support multiple high-bandwidth slots for graphics, we would think that there's no reason (other than driver support) to not want to have SLI support within a product family. The introduction of SLI could lengthen the GPU product cycles as performance can be guaranteed for much longer, but it could also increase the expectations of upcoming GPUs like NV50 and R500. We would not be too surprised if supply issues of many of the popular SLI cards developed right before the launch of a new GPU to prevent a lackluster introduction.
In the end we're rather pleased with SLI as it promises to increase the life span of your graphics card investment, something that we've been dying to have for quite some time. We will be sure to do a full review on the final shipping SLI motherboards and GPUs when they are available, but until then we hope you've enjoyed our preview.
Very special thanks goes out to Vincent and Iris of MSI for putting themselves and their engineers through hell in order to make this review possible. You would not believe how difficult this little benchmarking opportunity was to put together :)
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GhandiInstinct - Saturday, October 30, 2004 - link
I don't understand why you think X2's split work screen will be worse... Even if the scenes get more complex its still only half! So if a single X800XT renders the complex scene at 70fps then two will chop up? Your logic is FLAWED!!!TrogdorJW - Saturday, October 30, 2004 - link
61 - Sokaku, I wasn't any more rude that you were in your original post. You were incorrect in your claims, as #62 pointed out. I'll repeat: it was a claim without a whole lot of thought/research behind it. Certainly SLI isn't a huge step forward, but to call it a step backwards is ludicrous. SMP would also be a step backwards, and dual-core would be pointless as well. Obviously, the 22 year old webmaster knows quite a few things that you don't. Being wrong at the top of your lungs is why pure guesses aren't used when writing any professional level article.One thing I find odd is that there's mention of the new Scalable Link Interface SLI doing either screen division - i.e. one card renders the top 2/3 and the other renders the bottom 1/3 - or Alternate Frame Rendering (AFR). I thought ATI created and patented AFR back with their Rage MAXX card, just like 3dfx created and patented Scan Line Interleave. (One problem with Scan Line Interleave, for those that don't realize this, is that it basically makes AA impossible to do without a massive performance hit. That's why NVIDIA calls the new SLI Scalable Link Interface.) I can't see ATI allowing NV to use AFR technology without a lawsuit, unless there was some other agreement that we haven't heard about.
IamTHEsnake - Saturday, October 30, 2004 - link
Come on ATi, surprise me!!!!!!!GhandiInstinct - Saturday, October 30, 2004 - link
In addition, I hate overhyping brand new technology, it's so pointless. I can see analyzing this 6 months from now after people have been using it and more benchmarks are revealed.GhandiInstinct - Saturday, October 30, 2004 - link
No one is debating that SLI delivers phenomenal performance. The issue is with the limit on manufacturing creating an "SLI monopoly" lol.Everyone knows Nvidia cheats on visual quality and that ATI's cards perform better on an overwhelming amount of games. So if I have $400 to spend on my SLI setup I'd go for the latter of cards. Get it? It's nothing complex here folks.
mkruer - Saturday, October 30, 2004 - link
Here is my 2 cents on SLI.I think there is a misconception buying two 6600GT at the start, and thinking its is going to be cheaper then a single 6800GT is incorrect. The TOC (total cost of ownership) for people jumping on issue of just is not there. Currently it is just as expensive as picking up a single card solution.
Here is where SLI makes sense.
12-18 months down the line the next latest and greatest game will arrive demanding twice the processing power that you currently have. Now you could purchase the bleeding edge graphic card for another $400US or you could pick up another 6800GT for half that and get nearly double the performance (that would also translate into the same performance of the new card), if not better. TCO is now about 75% of picking up a new bleeding edge $400US card.
So I guess my recommendation to all of you out there that are thinking of picking up two 6600GT, don’t. Spend the same amount of money and get the 6800GT, and in the next 12-18 months pick up a second 6800GT for half the price, and you will still be getting the same performance as nVidia’s next generation, but for half the cost.
Possible future.
ATI is undoubtedly working on a similar solution, and possible working on a few “flaws” in nVidias current design, namely the SLI bridge connection. I suspect that in the future the SLI bridge connection will disappear completely and instead, be migrated to the last 8x of the 16x pci-e connection, thereby creating a direct point to point connection between the two cards. The advantage of this is now both cards could share there collective memory similarly to how AMD does with it processors between memory banks. This will allow for two 256mb cards to truly act as one 512mb card.
Tides - Saturday, October 30, 2004 - link
dual core gpus in the future?Sokaku - Saturday, October 30, 2004 - link
#62 - PrinceGazThanks for clearing that up, I stand corrected. :-)
Ivo - Saturday, October 30, 2004 - link
The enthusiastic market, where the two graphic cards SLI solution is positioned, is something like the F1 by cars: it advertises and proves new technologies, but it doesn't sell directly in profitable quantities. Probably, the mainstream market will never adopt it, at least because it is too expensive and too noisy. Nevertheless, a modified SLI solution, with IGP and ONE graphic card, could still be interesting for this market. In that case, the card, a 3D accelerator, should be idle for not intensive 3D applications and the SLI should adopt effective combination of two unequal GPUs.Denial - Saturday, October 30, 2004 - link
I'm glad I can buy anything I want at my job as the CFO doen't know what a 6800GT is. "Uhhh, it keeps the flux capicitor cool."How long till the SLI boards come out? Better yet, that dual SLI board from Tyan. I hope all this is out before the new year so I can slip it in with all the other end-of-year hardware purchases.