It depends on your use-case. If I was making a file server then idle power consumption is all that matters because both of these machines will saturate a gigabit ethernet link[0] and a home file server is going to be idle 90+% of the time. If I was making a build server instead then I'd actually be using the additional CPU capacity.

[0] actually I wouldn't use either of these machines for a file server due to the lack of ECC, but you get the point.