I just ordered a Dell XPS 720 and it came with 2GB Corsair DDR2 SDRAM at 800MHz overclocked to 1600MHz.My question is I'd like to add another GB of ram can I just get a gig and put it in or does it have to be OC'ed too? Also should the gig be Corsair or can I use another brand? Dell had a 3GB or a 4GB and everyone knows 4GB doesn't show on 32bit Vista so....?