I've recently shelved my DA to go back and tryout my trusty IMO (I believe its the 6000 fps version), but I've noticed something that bugs me.

When I try to move my cursor in straight lines, usually horizontally, it will wave up and down vertically... it's extremely hard to keep it on a straight path unless I move very slowly or so fast that I can't tell..

Does this have something to do with the DPI? Or with its ancient optical sensor?