Quote Originally Posted by HippsieGypsie View Post
Welcome to Windows EightForums, dshvedchenko.

Thanks for posting your fix.

Wonder why that would work, though, since itís the same BIOS version.
1. I tried clear CMOS
2. I tried enter maintenace mode

Every time I put old CPU it was ok to boot Windows 8.1 x64.
But latest BIOS is 1 year later after E8400 was issued, so it shoudl support it.
I think this is kind of bug in BIOS that it writes something CPU depended during flash.
reflash with E6750 ,didn't help. Only re-flash with E8400 inserted helped to resolve my issue.

Before re-flash BIOS does not see Intel Virtualization option with E8400 inserted - after re-flash it shows it.