Computer power usage question

If my computer has a 600W power supply, does that mean it’s using 600W all the time or just during peak usage? It’s used for gaming… aside from that it’s virtually idle most of the time.

The rating on the power supply only tells you how much power it could, theoretically, provide. Chances are you’re only using 100-200 W while idling or doing less intense tasks. When gaming, that number is going to peak (my WAG is 300-400 W), but probably not all the way up to 600 W. Of course, this all depends on what your exact hardware is.

My G5 Quad has a 1100 Watt power supply. It idles at around 250 Watts. If I run a computationally intensive program, the power rises to around 400 Watts. You can buy a power meter called the kill-a-watt to measure your power consumption.