At the moment iam using XP Prof ( 32 Bit ), 4 gig ram and 5 accs.

Will be there a performance boost if i go with a 64 bit OS?

Cant really say it lags while i run 5 accs ( 1 PC ) but sometimes i have "keysend" lag so only 2 out of 4 slaves do the action i was sending from main acc. Iam using keyclone.

Or do i get a better performance boost if i buy a quadcore?