Quote Originally Posted by Philly_Boy View Post
I believe it stands for Pulse Width Modulation....
Thats correct.
A quote from Michael Hyatt
"Pulse-width modulation of a signal or power source involves the modulation of its duty cycle, to either convey information over a communications channel or control the amount of power sent to a load.

The temps vary according to the amount of power being used and/or how well they are cooled. (none of mine are above 40*C, but they are extremely well cooled) 50~60*C is safe; 60~75*C is warm and acceptable to some; anything above that, and I think they are too hot and you had better consider improving your (case) cooling."