My EVGA GTX 560ti cards in SLI have a recent problem.
When I apply SLI in the Nvidia Control Panel the card assigned to PhysX immediately maximizes its GPU, memory and shader clocks to the max 900, 2106 and 1800mhz respectively. There is no load on the cards and nothing going on.
When I disable SLI in the control panel the clocks will reset back to 51, 135 and 101mhz.
Does anyone have any idea why this is happening and is there a fix for it?
Do you have a second monitor attached? If so, that will cause clock speeds to idle at higher levels.
If not, it could be a driver problem. To fix, manually uninstall the drivers from the Windows Control Panel, uninstall anything Nvidia, restart the PC, then install the latest drivers using the "Clean Install" option.