my XFX dual fan 6870 won't run completely stable at 1000MHz core. i figure the voltage needs a lil bumb but many others say theres runs fine at stock 1174. tried changing voltage with MSIAfterburner but can't. accesses the voltage but doesn't change actual #s in GPUID or GPU gadget.
975MHz seems to be the highest with no problems, anything over and FurMark 1.9.1 turns to white screen and shuts down the Burn-In test. doesn't crash system or cause any screen problems. even ingame over 975MHz the games will just freeze and close to the desktop. all my old cards would get crazy artifacts and crash whole system when OC'd too far. nice change.