I have two Powercolor Radeon 7770's that I am going to crossfire. My power supply is a Raidmax RX630Z 630 watt. Im running i7 3770S, 2TB Seagate 7200 RPM, 120GB SSD. I need to know if my power supply is big enough to handle the crossfire? This build is all about low power, low voltage, high efficiency, high performance. which is why the smaller power supply is in place.