You might alsoc sonsider selling your S939 and getting a cheap C2D rig with a Pentium Dual Core E2140 (C2D with 1MB cache). The CPU overclocks easily to 2,8-3,2 GHz, DDR2 RAM is super cheap, and good OC Board like the Gigabyte P35 DS3 are under 100$ as well. Might be a little more expensive than getting a Socket S939, but the RAM and Board may last you a while.
I did the same thing, sold my DDR1 OC RAM, got me a used C2D + new Board + new RAM, and now I need to sell the S939 Board and Athlon 64 4000+. The upgrade will have cost me like 60? in the end, and it's almost incredible how much faster my new system is.