i'm at work, so i don't have the exact wording here... but...

i found the vertical sync and bit sampling to limit my fps. i unchecked the vertical sync and set the vertical sampling to 24 bit, 16 samples, 1 bit (or whatever it is.. the numbers are 24 / 16 / 1)

if you are using 1 folder, log in a single wow... set those settings, and exit. then restart all your wows. they should all get those settings.

and of course, setting your maxfpsbk AND maxfps is critical. if you only set one, you won't be limiting the fps

good luck,

Rob