2 GPU's NOT SLI Hurting performance. why ?

[dbee]

Hey all, been a while. Nobody can seem to help me with this and thought i'd ask my friends at tweaktown. Ok so my x58-ud3r does not like having both PCI-e 2.0 slots populated. I have my main card being a GTX 260 and threw an 8800 gts in to help with folding. Well this cuts my frames in half. The performance is just killed. Anybody dealt with this issue before and if you have, do you know of a solution ?

I have tried switching slots, changing settings in Nvidia control panel, i've tried everything i can think of and the only thing to work was removing the 8800.

All help is greatly appreciated... thanks

[Reggie]

Re: 2 GPU's NOT SLI Hurting performance. why ?

The GTX 260 and 8800 gts is not a valid combinatation unless one card is used as a dedicated PhysX card.

In this configuration, one GPU renders graphics (typically the more powerful GPU) while the second GPU is completely dedicated to PhysX. By offloading PhysX to a dedicated GPU, users will experience smoother gaming.

[dbee]

Re: 2 GPU's NOT SLI Hurting performance. why ?

Yes i am aware of this as the title of the thread states im doing NON SLI. sorry for any confusion. I have asked many about this problem and none can come up with a solution. It does recognize both cards, i can dedicate either to physx, everything looks fine there. And i am sure it was running off the 260 since evga precision was showing GPU1 ( the 260 ) with usage and the 8800 at 0 % while in game.

[Psycho101]

Re: 2 GPU's NOT SLI Hurting performance. why ?

Sounds like a strange one mate.

Could you have a look on the main window of GPU-Z and see at what speed the two PCIE slots are running. If the slot with the 260 in it is being throttled to anything other than 8x (ie if it's 4x or lowwer) that could explain it.

There is a thing in Windows power settings called PCIE Link State mode. Set this to disabled. I believe this setting lowers the link speed of PCIE slots to 4x when there ls low graphical load. I have heard of the setting getting "stuck and not allowing the lanes to be throttled back up.

Another thing that may help is giving a tiny amount of extra PCIE voltage in the BIOS. The extra card may (unlikely but possible) be causing a bit of VDroop oin the PCIE lane/controller voltage that could be remedied with a slight boost.