GA-MA785GM-US2H not recognizing x4 640?

green cup

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Dec 27, 2011
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Hello,
I just received an AMD Athlon II x4 640 for christmas, and it seems my motherboard won't recognize it (on boot, nothing happens). I flashed the bios (using @bios, as qflash was only searching for floppy drives) yesterday up to F12a, the most recent update, and the one gigabyte said supported this cpu.
http://www.gigabyte.com/support-downloads/cpu-support-popup.aspx?pid=3141

GA-MA785GM-US2H (rev 1.0)

It shouldn't be a socket issue, as my current cpu (x2 250) is a socket AM3 like the 640. I also really doubt this is a power issue, going from a 65w to a 95w cpu, when my psu is 500w

2gig x 2 Gskill 1066 ram
HD 4850


I'm wondering if the cpu itself is defective. I made sure it isn't a wattage issue, testing whether or not it will boot without the gpu, for both cpus.