also noticed this happen a lot. i've had to result to turning all settings right down to minimum, all effects off and then running 800 x 600. its not pretty but it is at least playable. however i 4 box on 32 bit XP 4 gig ram, ( i think 32 bit only lets me have 3 though? ) 3.6 intel dual core cpu. before wotlk i could box 4 with almost full effects at native resolution for my monitor at around 30 fps for my 3 mini's and 70-80 fps on the mains. now its 15 max mini's and 60 max on main with all effects off.