To find the maximum overclock of our card we used a combination of GPUTool and our benchmarking suite.
The overclocks listed here were achieved with the default fan and voltage settings as defined in the VGA BIOS. Please note that every single sample overclocks differently, that's why our results here can only serve as a guideline for what you can expect from your card.
The overclocks of our card are 990 MHz core (16% overclock) and 1450 MHz Memory (21% overclock). Very impressive! The card is not only quiet but also overclocks incredibly well. So far this is the best overclock of all our HD 5770 cards tested so far (HD 5770 ref: 925 / 1325, PowerColor 5770: PCS+ 900 / 1395, MSI HD 5770 HAWK: 970 / 1420).
Using these clock frequencies we ran a quick test of Call of Duty 4 to evaluate the gains from overclocking.
The actual 3D performance gained from overclocking is 13.9%.
Temperatures are comfortably low, even with the massive overclock. It would have been nice to see slightly slower fan speed settings with higher temperatures in return for even less fan noise.