You can almost double your profits by spending 300 on a 7950 (~600 kh/s) instead of 160 on a 7850 (~320). You'd also have a card that will be easier to sell back in the future (IMO) as the 7950 is a much superior video card. The 7850 w/o crossfire is already struggling on some of the newer PC games.
I might do that. I just have to wait a bit longer to get enough. I'm still using my trusty old 560ti for games
So you think the other parts are fine? Will I need more RAM? RAM is cheap as chips, so I don't mind that.
The PSU in the link you provided is crap. Look at the 12V ratings. First it is split into 2 12v rails. 2nd, each rail provides only 20Amps. Unless you're a pro always try to get a single rail PSU. My Antec Neo Eco 520W PSUs put out more 12V power than that crappy 600W.
If you don't absolutely need the case, I would say just build an open system (assuming no kids or pets). You can have it mine on top of a cardboard box no problem. Spend the $60 on a good PSU. A quality 600W PSU would be able to power 2 7950s no problem. This crappy one might even choke after 3 months of 24/7 just running one 7950. I guarantee it will not be quiet or efficient. Plus it would have crappy ripple leading to instability in overclock. Bottom line the PSU is the most important part, more than the card.
2nd, the mobo/cpu is fine, only problem is 1GB of DDR. You would need to to run Win 7 x64. So either run 32 bit or go to Win XP or Linux.
