Difference to Full-Screen and Windowed-Full-Screen mode
So, what is the difference?

Will I be able to notice any big changes?

(I mean CPU/FPS wise)

I never got the point.The point is that you can have other applications viewable at the same time. Same as when you maximise or minimise other windows so that you can fit others onto the screen. In terms of FPS / CPU differences I havent done any experimenting myself but recon you would see a drop in performance in windowed mode depending on your spec and setup.As Cathbad specified, the main difference is the ease with which you can swap between open applications in windowed (fullscreen) mode. Ideally the performance difference would be negligible, but this is something I suggest you simply try out.Thanks for the answers :o)
FAIL (the browser should render some flash content, not this).

Cataclysm is a trademark, and World of Warcraft and Blizzard Entertainment are trademarks or registered trademarks of Blizzard Entertainment, Inc. in the U.S. and/or other countries.

This site is in no way associated with Blizzard Entertainment