I finally figured it out what is going on with this BIOS.

The problem is the DRAM Clock Fine Delays. They can change after a reboot. What probably happens is that if you advance with 300ps and get a DRAM Fine Delay of 0T after a reboot something gets messed up and instead of advancing 300ps the DRAM Clock Fine Delays get delayed 300ps resulting in 14T.

This explains why Prime95 fails sometimes after a reboot.

Something else that I found is that it is necessary to have tREF in the BIOS that is calculated according to Intel specs.
With a closer tREF used that I should use for my memory speed I can run Prime95 + UT2004 almost an hour before I run into a General Protection Fault.

What I did is make some screen shots and send them to my contact at ASUS. I hope they can figure out what is going wrong.