NVIDIA's GeForce 6 SLI: Demolishing Performance Barriers
by Anand Lal Shimpi on November 23, 2004 10:23 AM EST- Posted in
- GPUs
Half Life 2 Performance
Given our recent focus on Half Life 2 performance, it should be no surprise that we start off our performance coverage with Valve’s latest title. The benchmarks we used for this review were created in house and are all documented (as well as available for download) in Parts 1 and 2 of our Half Life 2 GPU Roundups. One word of caution however, the benchmarks in those reviews used NVIDIA’s 67.02 drivers, however those drivers in particular do not yet have SLI support, thus we were forced to use older 66.93 drivers for this review – thus making our NVIDIA Half Life 2 numbers not directly comparable between these reviews.
Half Life 2: AT_canals_08
In this first demo we notice a couple of things; for starters, there is a small but consistent performance drop when enabling SLI. The reason behind this performance drop is because at lower resolutions we are still CPU limited with the higher end 6800 based GPUs, thus the additional overhead of splitting up the rendering and forwarding data from one GPU to the next for recombination ends up making SLI slightly slower than just a single GPU. That being said, no one would realistically have $800+ worth of video cards and run at 1024 x 768.
Looking at 1280 x 1024 there begins to be more of a performance benefit to SLI, but the benefits are not really significant until we hit 1600 x 1200. At 1600 x 1200 the 6800GT and Ultra are still somewhat CPU limited, but the 6600GT is far from it. Moving to two 6600GTs increases performance by 67% and delivers higher performance than a single 6800 Ultra, 9.5% faster to be exact. This scenario alone showcases the upgrade potential for SLI; purchasing a single 6600GT today allows you to run Half Life 2 at 1024 x 768 quite well, but adding a second card later on will let you run at higher resolutions (or more GPU intensive games). Assuming you can add that second card later on for less than you purchased the first one, your upgrade path actually puts you in a better situation overall than had you just purchased a single, more expensive card at the start. Keep an eye on this comparison between two 6600GTs and a single 6800GT/Ultra to evaluate the mainstream upgrade path benefits of SLI.
With 4X AA and 8X AF enabled, the situation changes dramatically. Although the performance gains are impressive, the pair of 6600GTs isn’t able to outperform a single 6800GT/Ultra. For 6800GT/Ultra owners, SLI enables smooth playability at high resolutions with AA and AF enabled. We play tested much of Half Life 2 with two 6800GTs at high resolutions with AA/AF enabled and for the most part the game was butter smooth; at 1600 x 1200 with 4X AA/8X AF enabled however there were some areas where even two 6800 Ultras would get choppy. But most resolutions and settings that were not smooth before on a single card were definitely playable thanks to SLI.
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Kolbe - Monday, February 14, 2005 - link
BUYER BEWARE!!first, I have this ASUS motherboard and two GigaByte 6600GT's. AFter countless hours of trying to get this to work AND of course upgrading bios and drivers, I came to find out that these two gigabyte cards are not certified by Nvidia and they will not work in the sli mode on this ASUS board. ASUS has not returned my calls or my emails, but gigabyte, bless their hearts, wrote me back and said in essence: "our 6600GT cards work on OUR board" so too bad. Thank God for Newegg and their awesome return policy. I am returning these two and getting one 6800 GT, but of course, not from Gigabyte!
mashie - Sunday, December 5, 2004 - link
It would be nice to see tests at 2048x1536. After all if you can afford the videocards for SLI I bet you can get a proper monitor as well ;)Denial - Thursday, December 2, 2004 - link
Again, why no vanilla 6800's? How would they compete with the 6600GT's in SLI? This is starting to get rediculous.nserra - Friday, November 26, 2004 - link
Sorry forgot link.http://graphics.tomshardware.com/graphic/20041123/...
nserra - Friday, November 26, 2004 - link
#69 Yeah i agree.But let me tell you i already see something that SLI will give me.
Having a 6600 and a X700 on the same PC.
piroroadkill - Friday, November 26, 2004 - link
I don't know if anyone's said this, but SLI is an absolutely stupid idea, why on earth don't they take the 3Dfx Voodoo5 approach and just stick two GPUs on one card? Surely this would yield similar benefits without special mobo requirements.. 16x PCIe is easily enough bandwidth to cope... then just double the amount of RAM on the card and surely this is more viable solution? sure it'd be an insanely costly card, but still cheaper than an SLI setup, and lets face it, once a single card can outpace your shiny new SLI setup, that SLI setup is going to look poor value for money and you're just going to waste both cards, it seems obscene.stance - Thursday, November 25, 2004 - link
will the new duel core amd cpus that come out mext year be supported by this motherboardstance - Thursday, November 25, 2004 - link
tombman - Wednesday, November 24, 2004 - link
ANAND, please answer:1.) Can you really force SLI for games with no profile in the driver?
2.) please make 2048x1536 or higher Tests (my CRT can da 2304x1440 :D)
3.) please make 8xAA Tests
4.) please check if HDR (high dynamic range rendering) in far cry works in SLI mode (other sites say no)
Especially # 1.) is very important.
If only games with a profile can run in SLI mode, SLI will not become very popular imo. We know nvidia- they will only have profiles for benchmarks and most common hyped games. For not so popular games there surely will be no profiles...
thx
tombman - Wednesday, November 24, 2004 - link
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