So the current source for my SoB crunching is my Athlon 64 3200, a mighty fine machine that's lasted me well for a couple years now. But I finally couldn't take it anymore and yesterday I ordered some more parts, one of which is a Athlon 64 X2 4200 (AM2 Windsor), to build a new machine. (Can't wait!)

I'll still be running the good ole' 3200, so the dual-core should more than double my current overall production. Does anyone know whether it's more productive to run one instance of SoB or two instances (one for each core)?