Although the CPU compatibility list doesn't list any Xeons at all, will the EP45-UD3P work with, say, a Xeon X3360/X3370?
I understand the X3360 is a "normal" C2Q Q9550 but with an added command (I/OAT??) and the X3370 is effectively a Q9650 so I see no reason why it shouldn't work with a P45 board - although, as mentioned, the compatibility list doesn't include them and, according to Intel's pages, the X3360/X3370 needs a 3200 chipset.
Yes, I know I could get the proper Q9550 or Q9650 but I'm led to believe Xeon's have favourable thermal characteristics (and they're pretty much the same price as each other too!).
Cheers guys.