Well I have a little Dell Optiplex 745 SFF, which has a 1.8ghz C2D at the moment. It's getting 4gb RAM & a HD6450 in the next couple of days & am debating on whether or not to upgrade the CPU while I'm at it.
I'll be playing nothing too intense - GTA (III, VC, SA, IV), ARMA II (DayZ). All of which the card can handle well enough. I'm just wondering if the CPU will be up to it too.