Just put together a new build that runs great, except for SLI performance. Although I have moderate knowledge about computers, I'm completely new to SLI.
i7 2600k @ 4.5
Maximus IV extreme mobo
2x GTX 570 sli
ripjaw x @ 1866
ax 1200 psu
I get the same FPS using 1 or 2(sli) GPUs. I noticed that when I have 1 GPU activated that my GPU usage is up to where it should be, 90%+. When in SLI it seems like the GPU utilization is what it would be with 1 GPU, just cut in half and distributed with the two.
For example, in COD: Black Ops i get 91 FPS when SLI is activated and also 91 FPS with 1 card activated. With 1 card the GPU usage is about 94%, but with SLI it is 42% on one and 42% on the other. This happens with EVERY game I've tried. Mass effect 2, TES: Oblivion, The Witcher 2, Shogun Total war.
The ONLY application in which this isn't the case is Unigine Heaven benchmark. While running this program, everything looks A-O-K. I get an avg of 108 frames at the end of the benchmark and during the entire benchmark i get 90-100% utilization of both cards.
This doesn't make sense to me. Why would SLI work only in Heaven benchmark? Why is my utilization so low while running sli and why am i getting the same FPS while using SLI and 1 card?
Well, I know CoD:BO doesn't have a frame cap because I have reached much higher frames that 90FPS with my hd6850. I too have never done SLi, but do you have the bridge on? I would assume so, but you really don't need the bridge to run SLi, it just helps in DX performance. Also, what is your monitor refresh rate? If it is 90 hertz and you have vSync on, then you are capped at 90. Also, what is your monitor refresh set at?
The Witcher 2, if you are using the Ultra settings, will turn on v-sync, which caps your FPS at your monitors Refresh rate, which is normally 60hz. I don't know about the others you've tried, but you might have v-sync enabled, which would cap those at the monitors refresh rate.
It's actually a good thing to cap your FPS at your refresh rate. The only problem is that most the time a single 570 is enough to cap your refresh rate, making the 2nd largely not needed. However, if you played games like Metro 2033 and Crysis at max, then you'll notice a difference.