Depends on the heatsink, if it is stock, than it is actually good. There are no concern to both power and temp, it may however be a bit noisy, which you already know.
My PC at work runs on 43 idle 24/7, and probably will reach 70 easily with prime95. It never ever dies even though it does heavy computing at night. Actually, it isn't idle as the system is constantly computing with GPU, but the CPU is free.
If heatsink is mounted properly and you ain't overclocking, you don't need to worry about temp. When temp causes problem, your system will throttle (slow down) to protect damage, and shutdown automatically when temps gets too high, which you are no where near those temps atm. If you were able to run prime95 for several hours then your system is stable. The system won't get to whatever temp you see with several hours of prime95 even under heavy load, so there is nothing to worry about.
Last edited by Seero; 02-11-2011 at 10:28 AM.