ASUS P5B-Deluxe; Problems & Fixes

[chuckbam]

I tried 8 x 400 and it wouldnt boot at 1.375 vcore

tried at 8 x 375 (3ghz) and it boots but my PCIe gone back to 1x

memory is at 750

With
my motherboard a setting of Vcore 1.4375v = 1.35 ~ 1.39v

You need to do that default thing again. Strange, I have not had the 1x problem for over a year. I would read if you should flash to a old bios and flash again w/ the new one.