Im planning on getting a Foxconn A7DA-S 3.0 motherboard with an AMD Phenom II X3 720. I want to run 2 XFX 4850s in crossfire, i have a 500 watt psu in the raidmax smilodon case. It says a minimum of 550W PSU required for Crossfire. So do you think that the 50 watts less my psu has will affect powering the cards? Since im not going to be using a HIGH powered cpu or anything like that, except i will be OCing the cpu.