from the preformance results, you can see that there was either a large or almost invisible FPS increase in some games/software when using the AM2.. so for the extra like 5 bucks.. or depending on how much you want to upgrade/the jump in money for the Mobo and DDR2 ram. just make sure your processor is a AM2 socket and you have ddr2 ram if you're upgrading.
post your mobo/ram specs if you can get your hands on them