Ledge, ditch the F5 BIOS, it did not play nice for me. Try the F7a beta BIOS. I was having trouble with 4GHz and a lot of voltages as well w/ F5. After flashing to F7a, I can run 4GHz with 1.3175v set in BIOS w/ LLC enabled giving me a rock solid 1.29v according to cpu-z, OCCT and ET6. I also only have 1.35 PLL, 1.22v cpu termination and 1.32v MCH. It SHOULD make a big difference for you as well.
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