Ok then there is where it could be coming from in the difference in temps. I am not sure on the SLI block you using but if you can go into parallel config you will find the temps should be the same on both GPU's with a max 1 degree difference compared to what you have now. Also i think you will be better of in a parallel config there. There is more info on it on OCN. I know with serial you are transferring more heat from one GPU to the other i had the same problem once and went parallel and all was sorted temps dropped on both cards to 1 degree difference.
Edited by BazG - 3/12/15 at 9:07pm