the delay in pip swap is related to wow. as it resizes to the new dimensions, i believe it is re-rending some surfaces.

to improve your performance, definitely reduce your details and make sure the game resolution, found just under the PiP hotkey field on the maximizer panel, is the same for all regions. also, make sure the regions are all a scaled ratio from the main region.

personally, i set the game resolution for all regions to the region dimensions of my main region. on my quad core (8gb memory and an nvidia 260 on vista64), my pip swap takes about 500ms ... but my details are usually at medium and my fps are set to 30/45

i hope that helps,

Rob