This card earns a Gold award from OCC for its nice and quiet operation, good overclockability and good operational temperatures.
"Overclocking the PowerColor 6790 was simple using either AMD Graphics Overdrive with maximum speeds of 950MHz core and 1250MHz memory or MSI Afterburner v2.1 with the clock limit unlocked in the MSI Afterburner.cfg file for higher capabilities. Software voltage modification isn't supported yet. Even so, I managed to game for a while at 1010MHz core and 1260MHz memory although the system would freeze randomly. Turning the settings down, I didn't achieve reliable stability until 1000MHz core and 1235MHz memory. The card may be able to operate stable over 1GHz but was bumped down to make sure it could pass through all of the testing. It was likely the memory which was the culprit but it still managed to overclock 185MHz over stock"