I have a 400W PSU, and I'm not a hardcore gamer, so i've bought this GPU (although a sapphire branded one). It runs cool, makes very little noise and consumes very little power. The catalyst overdrive utility enables you to safely overclock your card... i got a 75 Mhz increment in the GPU clock speed and a 50 MHz increment in memory clock speed, got my windows experience rating up to 7.0