People avoid full ATX boards due to size considerations. If you've got the space for it, use what you got.
The CPU, on the other hand...
That could be a potential issue. It is a high power draw CPU, which can cause problems.
The max draw on the 12v rail will be around 8A (95w / 12v = 7.916A) for the CPU itself. Factor in the motherboard, hard drive(s) and optical drives and you're pushing dangerously close to the 10A limit on the 12v rail for the M4.
If you were to replace any piece of that system, I'd look at a 65w CPU to keep your potential power draw well under the limits of the PSU.