I know I am late on this. I have this mobo with a Q9550 running unstable for to long.
I did the bios update required.
After installing compatible RAM modules I still experienced unstability (pc freeze) even though the RAM was set to factory setting manually.
The problem could only be the CPU settings. I always had these settings set to [auto]. So I underclocked the q9550 to 1066mhz FSB. Now all is fine...