Question : Problem: Opterons incompatible with server motherboard?

We've got a server running Windows Server Standard 2003.  It currently has two Socket 940 Opteron 246 processors running at 2.0ghz.  The motherboard is a Gigabyte GA-7A8DW, running BIOS version F4, which is the latest version available.  The latest chipset drivers are also installed.

We attempted to replace both processors with Socket 940 Opteron 254 (2.8ghz) processors.  The system booted, and we were able to get into the BIOS, but were not able to boot further than the BIOS or load Windows at all.  It seems as though the BIOS and motherboard recognize the new processors ok, but Windows does not recognize them.

Is there some sort of incompatibility with this particular processor and the motherboard?  Or some sort of update that needs to be applied to allow the new processors to run in Windows?

Answer : Problem: Opterons incompatible with server motherboard?

That motherboard supports a maximum bus speed of 800 Mhz which matches the Opteron 246's.  The 254's run at 1000 Mhz (1 Ghz).  I suspect that they don't like to be underclocked.  There may also be a Vcc (core voltage) difference in the CPU specs.