I'm running on the following stats, and Alpha ran at 60fps full time, on max settings. Didn't use the unlimited fps option.

MOBO: ASUS CrossHair III Formula
CPU: AMD Phenom II 955 BE OC @ 3.8Ghz
RAM: 4GB G.Skill 1333 DDR3 RAM (Win7 32bit - So only like 3200MB usable)
GPU: AMD Radeon 7700 HD Ghz Edition (OC@ 1.2Ghz Clock - 1.125 Ghz Memory)

It only cost me about 360 bucks to upgrade my old rig to this. Only old part left is my DVD drives and HDDs.