lol iam using 850 watt on crossfire 6970..24/7...nonstop...ok ra kaayu na 500watt brad pero if you can get 600 much better...according to my power watt reader single card consumes 300+ watt on non overclock system..
edit: this is 100% full load @ 99% gpu usage plus 60% cpu ussage using olhascat software..