Here are my observations on this board. You really need to adjust CPU and MCH reference voltages (GTL's) on this board. Most seem to be using auto which is fine for stock. CPU termination and MCH voltages default values are 1.2 and 1.1 volts, respectively. At these voltages the reference voltages default to 0.760 volts. This corresponds to a CPU GTL reference of 63% (0.760/1.2 = 0.633) and an MCH GTL reference of 69% (0.760/1.1 = 0.691). These values may not be suitable for the overclock you are trying to obtain. Manually set these voltages then start raising the CPU termination voltage. You will see the CPU and MCH reference voltages rise also. Note that the ratio of CPU ref./CPU term. is always around 63%. This is what the auto setting does, changes the CPU reference as the CPU termination rises to keep the 63% GTL. While this is the generally accepted value for 45nm CPUs, a ratio is 67% is preferred for 65nm, especially quads. For example, if your CPU termination is 1.3 volts, choose the CPU reference of 0.863 volts (0.863/1.3 = 0.664.

Another problem arises with the MCH reference. If you leave it on auto the BIOS will set it to the same value as the CPU reference. So if you set the CPU termination to 1.3, the CPU and MCH reference will be 0.823 volts on the auto setting. But if you have set the MCH to 1.4 volts, your MCH GTL is 59% (0.823/1.4 = 0.587) which is likely too low. I found that while Linpack, Prime small FFT and Blend would all pass, large FFT would eventually cause a lock-up if the GTLs weren't set correctly. For my Q9550 on the UD3R I found that using 1.3 volt CPU termination and MCH with both references set to 0.863, giving a 67% GTL for each, gives me total stabilty at 475 x 8.5. Of course each board/CPU will be different so you just have to test.