When you are experiencing the sluggish mouse, that's because you're hashing at the maximum rate (it is using your video, which causes that to happen). When you aren't experiencing that, you're only using part of the power.
Thank you... but my CPU usage when running the 50miner program is only at 50% the same as when i run 2 miners on GUIminer and i have no lag when i use that program. Thats what is puzzling me if it was using 100% CPU then I would understand but its not. and do these progeams use bith my cards or just one... and if not is there a program that will use both cards.