So, I have been around the internet and back on this and I feel like I've learned nothing.
I have 2 560 ti's in SLI, both of them EVGA, both of them the reference design, but one is the FPB and the other is Superclocked. have tried clocking and volting these cards the same, as FPB SC and over clocks, but almost all I have huge stuttering or stability issues. Currently I am only running one of them because it feels more stable and smooth in games. (Which sucks because I currently cannot utilize my Nvidia Surround setup)
That is really odd you should just be able to overclock the other card to the same level if you want. If you don't want to, then the factory overclocked one will downclock itself to the same level as the normal card. i will look into to helping you figure this out after i eat no worries.
I would like to add as a solution, try default clocks on both cards, meaning have the clocks as the manufacturer made them. Then turn on SLI and of the cards should match each other through the SLI software. See if it does anything.
Oh and make sure both cards have updated drivers. If not, take out one card, update it, and repeat with the other card.
Afterburner has the cards synced to the same clocks all the time. It's the superclocked settings. (900 core, 1800 shader, 2106 memory, 1.075v)
I'm running 301.42 drivers from nvidia, and the latest firmware (1.0, evga hasn't released a new firmware for these cards) I'm wondering if I should RMA both cards get fresh ones, and see if that helps?
bigcyco1, thanks! your help is greatly appreciated.