Earlier this year, I was running Aces on an 2.2mhz opteron server board, with no problems. Now I'm running a dual 3.06mhz Zeon system - again with no problems.
Personally, server boards usually run toward the expensive and don't really give anything to brag about. The only reason I'm running them, is because I acquired the Cpu's and memory for practically nothing, so it was worth getting the mtb's.
Find yourself a nice gaming mtb, like one of the Asus boards and go with that.
Wabbit