Without voltage changes and at AUTO fan settings, our overclocking resulted in 875MHz for the GPU. This is not a bad result all things considering but if you crave more, you’ll have to resort to upping the voltage. Gainward GTX 570 GS GLH allows for voltage changes via the Afterburner tool, which we used. The card runs at default 1000mV whereas upping it to 1150mV allowed us to push the GPU to 950MHz and the memory to 4200MHz (effectively).
Idle temperatures were around 46°C whereas intensive operation resulted in about 77°C, which is pretty nice. Our overclocking raised GPU temerature up to 85°C.
The fans are not too loud but are louder than on the reference card. Although we expected a bit quieter operation in intensive GPU utilization scenarios, we were pretty happy with idle “noise” as the card was almost inaudible.
Although the fan tachometer doesn’t report RPM variations, our test card made a somewhat howling, high frequency noise. It is possible that this is a mechanical fan flaw and it could be an isolated case. Good thing about the cooler is that it keeps the card 8°C cooler than the reference card (77°C compared to reference cards’ 85°C).
Gainward GTX 570 GS GLH's higher consumption is partly due to the factory overclock and partly for different power regulation. If you recall, Nvidia made a consumption regulator which prevents the GTX 570 from exceeding predefined consumption.