no, the maxfpsbk to 3 or 4... this means that when your alts are not in the foreground (not active)... then the frames/second will drop to 3 or 4.. saving loads of cpu/gpu

but you also need to set the maxfps to 40, otherwise it will try to get 999 fps, which is unneeded and a waste of cpu/gpu

just set the fps range in the command editor, under the wow:username