Even so it is not an officially listed cpu (Xeon 5504)for this motherboard, it is working properly on my 1366 motherboard and cannot spot a faults at all when at stock speed. It was Over Clocking well up to 2700mhz just for testing, in the past.
Well, the other day I started to O. C. And the system does not boot at all and does need a bios reset. This is a 2000mhzx4 cpu and tried whith the lowest O. C. At 2001mhz and it does not boot believe it or not. Now, what do you think the problem could be? The cpu works very well at stock speed and until last time I was able to O. C to 2700mhz without any problems at all.
Could it be possible that the cpu controller is gone faulty? Well, if it is gone faulty, then it should also be faulty at stock speeds, I think. Tried everything, voltage etc... But not any success yet.