for some ppl in beta, theres a video setting that, when it set to full it actually is set to lowest. i can't recall wich setting it is, but i clearly see less detail on my screen when playing, and tbh i got so tired of the lag, that i only saw sw harbor and the harbor at northrend. i went to kill some mobs to test thunderstorm, and that was it.

just saying this, because u might be telling it runs smoother with everything on high, when in fact theres a bugged option setting it to lower.