Hello, Trying to squeeze a little more performance from my rig, I set my Sapphire ATI Radeon HD 5770 (using Sapphire's triXX tweaker) core/mem clocks to 1000mhz/1400mhz respectively. Under normal loads (browsing and such, no heavy gaming) its idle temperature hovers between 38 and 42 C.
I had tried upping the GPU voltage a few ticks when I first was increasing the speeds, but when I hit "apply" the voltage setting automatically dropped back down to 1125. That seemed weird, but I've had no video glitching at the higher speed so far.
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If you are under 80°C under load you are fine. Max would be around 100°C.