Reverse engineer. Blogger.

Good tip from Rob LeFebvre on Cult of Mac:

You might notice that your hard disk is constantly spinning on your Mac. If you check Activity Monitor, you might find out that the CPU is also being used up by the Finder, which typically doesn’t use a lot of CPU.

Turns out that the culprit could, in fact, be video files on your desktop.

I had two video files on my Desktop as I read this tip. I removed them and within minutes my Mac’s fan spun down. Coincidence? I think not.