Well, turns out it's not maximizer's fault! (changed subject accordingly)
Having the same issues running normal windowed mode... Interesting thing though, if I check the windowed mode checkbox and then the one below it (full-screen?) it runs fine, but as soon as anything non-wow related pops up (whether it has focus or not) FPS drops to 1-2....

So, what could cause that? I do have the latest drivers available for that card, though it's over a year old... it just not being updated anymore.

Clues? Ideas? suggestions?