well the 3800+ X2 would still out perform a 3200+ because even though the game is single threaded the other core is still working with Windows and any other background programs running. Although there won't be much of a performance increase.
beefcake has it. The 3200 is 2.0ghz with 512mb cache. When you get up into the 4400+, you start comparing the cores to the processors with the san diego core, like the 3700 and the 4000.