Hello, I ordered a BFG 7900gt. I was wondering if my current psu, a thermaltek 430W with an 18amp 12V rail, would be enough? I have an AMD 3500, a gig of ram, an 80 gig hard drive, and a dvd rom drive. BFG recommends a 350Watt with a 20amp 12V rail. Nvidia says a 350W with a 15amp rail is...