Ummm, first off, you aren't on the best track for building a comp. IMO
You don't start with the case and video card.. (which by the way if you're doing SLI they have to be the same kind I think)
It goes like this.
CPU>>Motherboard>>Everything Else
Because the CPU determines what kind of motherboard you'll have and then the motherboard determines what kind of stuff you can have in the comp like how many hard drives etc.
I'm planning on building a comp soon, when I get the money, and I'm going to try to get it to be really cool like 30 C at most. It'll most likely be an AMD X2 2.4 ghz or maybe more but I'm not sure, and then it'll have some kind of motherboard and 4gb of ram unless I find a decent motherboard that supports 8gb then I'll still have 4gb but they'll be 2gb sticks. Anyway, just hope I helped.