Cpu usage at 100% but only 40 deg. cel. is that bad

Question

I am rendering a Blender video for my friend and its been going for the past 4 hours at 100% usage but max 40 deg. cel. I am wondering if I leave it on until I wake up?

If the video finishes in the next 3 hours, will it damage my CPU to the point where I will notice it while playing my games? I am very worried because I don't know if it will go up in deg. or break my CPU.

I am currently running a FX 4350 at 4.2ghz max temp is said to be 80 deg cel. and right now it is half. My cooler is a CoolerMaster Hyper Evo 212.

Edit: In between each frame which is average every 3-4 minutes for a good 5-10 seconds the usage will drop to 30-40 usage and the temp will go to 20 or so then go straight back up to 100% and 40 cel.

Answer 1

Look at this link to show why you don't need to worry about it - CPU's are built in such a way as to slow down to stop themselves from getting damaged by generating too much heat - so you don't need to worry about burning your out.

(This would address Axel Kemper's concerns about a fan stopping to work as well - that, and the fact that there is not much that can combust in a system which is overheating - so your home is relatively safe).

Answer 2

40C is a great CPU temp. I also render with blender, but I'm using an overclocked i7 6700k (from 4.0GHz - 4.8GHz) that I usually let run overnight running about 70C temps. You should see no performance reduction whatsoever (CPU failure is very rare). If your CPU fan fails, the computer should shutdown to prevent damage (unless you've disabled it in the BIOS).