What resolution is she using? Lowering it by 1 will improve her frame rate.
I've never played WOW but if it has a frame limiter then there may be a way to disable it. Look in the WOW folders for a .cfg file. If you find one do a page search for fps, frames, etc... If your lucky you may find something like MaxFrame=60 or Smoothframe=60 or something simular. If you find something simular but your just unsure post it and we'll have a look see
