I have checked more than ten mouses at different times, the best result for drawing (technical drawing) is with the logitech mouseman (NOT CORDLESS), because the ball in it is greater and heavier than all others and allows a finer cursor-placing. Think in geometry, with a smaller ball the diameter is smaller, means for the same distance the smaller ball must make closer way and couldn't placed accurate. I used the wacom-tablet at COM-3 and the mouse at COM-1. A technician in our company had let me know, it's possible to use 3 different mouses at the same computer: 1st at RS232, 2nd at PS2 and 3rd at USB Hope could help you. SHARKEY