I am currently running an AMD Phenom II x4 with 12gb of cas9 Gskill 1600 DDR3 RAM on a Gigabyte 790XTA UD4. My PSU is an Antec Earthwatts 650. I also have 60gb kingston SSD on the way. I am wondering if anyone would recommend a PSU upgrade to crossfire two 6850s? I will probably want to overclock them, and if I run into any bottleneck issues, I will overclock the PSU. I just really don't know if the Antec EW 650 can handle it properly? Any thoughts?