I'm having a hard time getting it stable at 4.05GHz, DDR 1199 and tRD 6 with Prime95 and UT2004 together.

Everything runs fine, not a single sign of instability. The problem is that just before it's running for four hours it becomes totally unstable and reboots like someone is pushing the reset button.

I tried with giving it more FSB Termination Voltage but it didn't help. I tried with a little more NB Voltage but still the same. I tried with changing tREF to 4680T or changing the CPU and NB GTL Voltage Reference but it doesn't help.

I can run 100 passes of LinX stable and my memory is 1000% MemTest for Windows stable.

The only thing I didn't try is changing the PCIE Frequency. I'll give it a try with 110MHz to see if that fixes something.

The only thing that I find odd is that if I start a 3D application (UT2004) my memory frequency starts to fluctuate between 588MHz and 602MHz in MemSet.

Did anyone else have this problem when running a 3D application?