I think the E0 E8400 in my main rig has degraded, I can't seem to get 4GHz (500x8) stable anymore. It was originally in my DFI UT X48, ran that for quite some time. I reset to stock to do a Vista > Win 7 upgrade and left it running that way for a while, but when I tried to go back to 4GHz it wasn't having it. I swapped boards and put in my UD3P thinking maybe the DFI was to blame but no go even with vcore set as high as 1.35v! It used to be fine running about 1.25V on load at the same speed I've tried VTT from 1.20 to 1.30. Very strange.