in a long run, its better to upgrade to AM2 socket because AMD is going to release an AM3 socket, it backwards compatible with the AM2 socket, but the AM2 processor wont work on the AM3 Socket because of the memory controller. AM2 socket will only support DDR2, while AM3 will support DDR2 and DDR3.
But if you want to stay with 939, its your choice.
though, i am not sure if theres any performance difference.
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