id check your grounds under the hood, battery, and the engine grounds, and the plugs to the motors, clean them up grease em up work the plugs in and out a few times.
also check the wires for damage as they come in and out of the doors. also the window switch plugs, clean and grease them up. and inspect for damaged wires there as well.
if you have a volt meter, you could test the draw off the wires while working the windows as well.
and are you doing this with the car off? or running? running (idling) parked, my window are kinda slow, driving down the road they move much faster. parked, engine off they are so slow its painful. and only get slower and slower as they steal from the battery.
