Vista / WoW seems to be self-limiting the FPS

I've been having trouble with my main instance of the game (running 5 on one box) randomly locking itself down to 30fps even while focused. This is usually only temporary and it jumps back up to 60 within 10-15 seconds, however, it does prove to be fairly frustrating : (

I use Keyclone, however, I don't believe it is the culprit here as my main instance is set to run at 60 even while not focused. Has anyone else had an issue with WoW, Windows, or any other program doing this?

Thanks in advance!

start up ONE wow... go to wow/video/resolution and make sure 'vertical sync' is not checked. this would limit your fps to some whole multiple of the fps for the monitor

once unchecked, hit ok and exit that wow completely. this will force the setting to writ to disk. now start your wows normally (ie: w/ keyclone). all wows should now not be sync'd with the vertical retrace

Make sure your max framerate is not more then your screen refreash rate (ususally in HZ).