100% CPU Usage

[Siluro]

A program or a game don't burn processors;if that happens,this is because of weak/out of order fan ;inadequate fans cause processors to die very fast

I agree completely, and I would go so far as to say it was a faulty Fan/Heatsink seating that was causing your D2 errors, shavenlunatic.

As for the original topic, AFAIK pretty much all games will use 100% of available processor time because they are always trying to draw new frames. D2 is presumably capped at 100 Frames Per Second, so unless you see 100 fps constantly (type "/fps" ingame), then your computer will be constantly drawing new scenes every frame. Even if you were averaging 100 fps, I'd wager that D2 will still draw more frames and then simply discard them... bottom line: D2 will use 100% of available processor time where it can. If you're running a program in the background that demands a certain amount of CPU time at a high priority, it will get it and D2 will suffer.

Also, if you are running a Distributed Computing type research application, like Folding@Home, then this program will also cause your CPU usage to be 100% constantly. However, F@H and its ilk will only use spare, or unallocated CPU cycles, so they do not slow down your system whatsoever. Hope this helps.