SLi causing a reduction in performance!

[newtekie1]

This is with my main rig in my specs.

3DMark06 gives me 6370 with SLi disabled @1680x1050 Max Settings but when I enable SLi I get only 4369 at the same settings. This doesn't make sense to me, has anyone encountered this issue? Drivers are 177.92, I'm going to try a complete driver clean and re-install later.

Also, every time I enabled and disabled SLi, I did restart Rivatuner and re-apply my overclock settings to make sure the cards were always running at the same clock speeds during the test. I know sometimes the clock speeds will be set to the defaults when you enable/disable SLi.

Any ideas?

Edit: I have a little more info. Games are showing the same performance hit with SLi enabled. The BIOSes on the cards are different versions, but that shouldn't matter. Also, the second card in GPU-z says it's clock speeds are 0MHz. This is making me believe that the driver for the second card is not installed correctly.

 

[NeoCrisis]

Ive had the same problem after i flashed the bios on both my cards.
one of the cards isnt registering even if you keep installing the drivers. Basically the second card's clock speeds will half of what its defaults are (as same before you install drivers) so when you have SLI enabled both cards will have the slower clock rates hence drop in performance.
The only way I figured out to fix it is a clean reinstall of your OS.

 

[AshesOfThePlope]

apparently, im having the very some problem, i tried a clean install of my OS and it didn't fix it, but i noticed the same thing, tried both 177.79 and 177.92 same result with both

iv been trying all i could, i noticed it most when i tried both cards separately, then put them back into sli

 

[newtekie1]

Ok, I think I have fixed the issue. NeoCrisis was correct, the driver was not installing correctly for the second card, causing the clock speeds to run at 400MHz core and memory.

To fix the issue I followed the steps listed here.

After doing that I re-installed the 177.92 drivers, and both cards are not reported correctling in GPU-z and Nvidia control panel. I'm just running some tests now to confirm that they are actually running correctly. I'll edit this post when the benchmarks are done to let you know if it really did work.