NVIDIA's GeForce 6 SLI: Demolishing Performance Barriers
by Anand Lal Shimpi on November 23, 2004 10:23 AM EST- Posted in
- GPUs
Doom 3 Performance
As you can expect, SLI offers no benefits at 1024 x 768, but as early as 1280 x 1024 we start to see some reasonable performance gains. The 6800 Ultra gets a 22% increase in performance, while the 6800GT gets a slightly bigger bump of 26% thanks to SLI. The big winner here is the GeForce 6600GT whose frame rate jumps 43% from 63.6 up to 91.1 thanks to SLI. Here we begin to see some of the upgrade potential of SLI, with two 6600GTs offering slightly greater performance than a single GeForce 6800 Ultra at 1280 x 1024.
At 1600 x 1200 the 6800 Ultra sees a 39% performance increase in SLI mode, breaking the 100 fps barrier in Doom 3’s built in demo. The 6800GT gets even more of a performance boost at 53%, bringing it to within striking distance of a SLI 6800 Ultra setup. The 6600GT also becomes much more playable at 1600 x 1200 with SLI enabled.
Enabling Antialiasing simply increases the benefits of SLI. Now at 1024 x 768 there is a performance advantage to having two GPUs, and for the 6800 Ultra that’s a 34% increase in performance. Once again, the margins of improvement get better as you move to slower GPUs – 36% for the 6800GT and 66% for the 6600GT. At 1024 x 768 with 4X AA the two 6600GTs manage to offer performance that’s just slightly faster than a single 6800GT.
Going up in resolution we continue to see some impressive gains, but what matters here isn’t that SLI results in a 63% performance increase for the 6800 Ultra and 72% for a 6800GT, what matters is that SLI makes 1280 x 1024 with 4X AA and 8X AF very smooth, something that was not possible with only a single card. Despite the performance improvement, two 6600GTs are not able to pull ahead of even a single 6800 Ultra in this test, which shows you some of the limits of SLI. While the 6600GT in SLI mode does much better than a single 6800 Ultra at “lower” resolutions like 1280 x 1024 with AA disabled, turning on antialiasing still preys on the bandwidth and fillrate limitations of an 8-pipe 6600GT with only 16GB/s of memory bandwidth.
What’s important to note here is that the recommendation varies greatly based on resolution. While the 6800GT does incredibly well paired up with another card, the 6600GT only offers better performance than a single 6800 Ultra at non-AA resolutions. As soon as you enable AA, even a pair of 6600GTs isn’t faster than a single 6800 Ultra (or GT).
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bob661 - Tuesday, November 23, 2004 - link
#18The hardcore gamers would just buy new video cards.
reboos - Tuesday, November 23, 2004 - link
"Nvidia bought the patents, pending patent applications, trademarks, brand names, and chip inventory related to the graphics business of 3dfx."http://slashdot.org/articles/00/12/15/2244256.shtm...
fuzzynavel - Tuesday, November 23, 2004 - link
I think 3DFX were bought by nvidia...or at least the rights to the technology....so it is technically the same company...I remember the days of 3DFX scan line interleave....fantastic!bob661 - Tuesday, November 23, 2004 - link
#17Two Opterons would be downright scary if they were limited too. But a 4000 is no slouch. :-) It's still amazing. I happen to agree with #12 but the real test of that theory would be to test slower CPU's and see how the performance scales.
reboos - Tuesday, November 23, 2004 - link
Odd as it may sound, should we be thanking 3DFX for this?http://slashdot.org/articles/00/12/15/2244256.shtm...
Gnoad - Tuesday, November 23, 2004 - link
Although SLI is exciting, I found myself wanting more info on the Asus board...haris - Tuesday, November 23, 2004 - link
I just had some more thoughts about why SLI/Multi rendering might not be such a great move by Nvidia/ATI.When they launch their next generation cards they are expecting to rake in some extra money from the extreme gamers, right? What happens to that same card when they start purchasing relatively cheap last gen cards instead. This might then lead to something like this: In order for them to get that additional $ during the begining of the next gen card's life cycle they might have to slow down the production cycle of cards to give them more time in the high-end position.
Jeff7181 - Tuesday, November 23, 2004 - link
#14... why? You have TWO GPU's here... and ONE CPU. Why is it so amazing that two GPU's can put the squeenze on one CPU? Now... stick a 6800U SLI setup with a couple Opteron 250's with an application that's multi-threaded and THEN I'd be amazed if it was still CPU limited.Aquila76 - Tuesday, November 23, 2004 - link
Or was that 330 Watts the total system usage? (doubtful)Aquila76 - Tuesday, November 23, 2004 - link
What power supply was used in your testbed? If the SLI setup requires at load ~ 330 Watts, I would think you'd need around a 550W unit for your setup.