Idle at 80, load 100. That's about the same as my foiled 3 way 4890 CFX project. Is it stable for continuous use at those temperatures?

My current (2 way CFX) idle 65-70 and load 80-90 also I think it's too hot already. Changing casing soon.

Now you tell me... hahaha okay then, 3 way 4890 CFX is back on the cards, along with a better casing. Can't add extra fans on my Raven.

Yup, just get a 1000W+ PSU if you're planning to use SLI/CrossFireX now/in the future.

No point in getting lower ones and then having to upgrade it later when you decide to run SLI/CFX.

Future proof + piece of mind.

Not like you'll end up using more power than what your system needs anyway. If anything, higher end PSUs are more efficient, so you might just use a bit less power compared to cheaper ones.