I have a i7 950 OC @ 3.9 and a Sapphire Radeon HD 6870 that I would like to over clock as well. Whenever I raise the clock speed of the core and the memory higher than the defaults and try to play Battlefield BC2 the screen freezes after playing for about 3 min. I am using the ATI overdrive with aprox. 950-980 core and 1100-1180 mem. Well under what that card can do stable. Any ideas?
Make sure your card isnt overheating to begin with....run gpuz in the background and have it log the temps for you......if that is not the case start at stock speeds and make sure it is stable for you there...if it is increase the speed in small increments like 5mhz at a time....it could be that your card doesnt like that high of an OC....there really isnt a standard as to what cards can do it all depends on the manufacturing of the card......if you really want to get the oc to be higher you could alter the voltages but then you risk frying the card if you dont know exactly what you are doing