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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kongming - Wednesday, November 24, 2004 - link
What I would like to see is the SLI performance increase of the ASUS V9999 6800GT with only 128MB of memory compared with a stock 6800GT with 256MB. If this card gets a particularly good boost from SLI, That would make it an even better deal.coldpower27 - Tuesday, November 23, 2004 - link
Well there's also the rumored that next generation cards will not be double performance, as it's likely were going to see 6 quad solutions from NV and ATI next year, 8 quad is just too much, for even the 90nm process to handle. THough I would be pleasantly surprised if it's not.Drayvn - Tuesday, November 23, 2004 - link
What im wondering is what happens if its something like the 9800pro then a year later we got the X800XT-PE or UltraIt was twice as fast, and in terms of technology we have SM3 also which we now have in 1 game.
9800Pro's performance was doubled by the PE and Ultra. So what would happen when lets say if SLI came out then.
Why would anyone want to buy another 9800Pro? Since u could get the PE with a few added features which are being used now...?
IT doubles the performance and with the extra features it further expands that performance gap. So is buying 2 9800pros worth it. Especially when they are still really expensive
Of course this is all hypothetical, and i love SLI but what im getting at, is it now time that nVidia and ATi will slow down their product life cycles?
Will they now have no refresh cards anymore, since when they bring out their next gen cards, 6 months down the road there is no need to buy a refresh as that only adds little performance and everyone can just buy another card for the same price and get double?
ceefka - Tuesday, November 23, 2004 - link
PCI-E, SLI, it´s all graphics so far. Can this technology also be used for soundcards? Can we have 24 channels of 192KHz/32bit someday on PCI-e SLI? If so then the whole bunch should be reconfigurable meaning that you can spread capacity equally over all slots or place emphasis where needed. If that's where we're heading, we're in for some exciting computing.R3MF - Tuesday, November 23, 2004 - link
#30 is correct, SLI for the Geforce 6 generation makes a lot of sense if your pockets are deep enough.SLI for Geforce 7 will be a different proposition, the imminent move to 0.9u and DX10 will create a generational leap when Geforce 8 arrives, so running two Geforce 7's won't be so clever.
bob661 - Tuesday, November 23, 2004 - link
I think SLI is worth the money and the present games can use it. But damn is it expensive. I'll still get it though. :-)KAM04m - Tuesday, November 23, 2004 - link
I personally think SLI is not worth it for the money. Plus i dont run the game at 1600x1200 only 1024x768. SLI setup prices will drop in the future and thats when the newer games will really need the extra bandwith! Until then AGP is still my bud for another year.sophus - Tuesday, November 23, 2004 - link
cpu limited...? anyone care to theorize if dualies would help increase performance? or what is the limiting factor (bandwidth)?sophus - Tuesday, November 23, 2004 - link
Filibuster - Tuesday, November 23, 2004 - link
#33 you can find a few XFX 6800GT PCie cards on pricewatch but they want like $550 for them.(I just looked and they are not there anymore though)
There was a reference card on ebay the other day for $400 though...
They are basically impossible to get without paying a rediculous amount for.