With all my respect, please read your response here.
Thanks, but I'm not turning Video Acceration down. I've never had this problem with other versions of Sonar-- just 6. I've never had performance problems with my other software. I can run the fastest games, 100 track sessions, etc. The computer is plenty fast enough. If anyone knows of a better resource that lets you see all of your IRQs at the same time, that would probably help most.
You posted saying you had a symtom that was manifesting and it appeared to me that you were asking for help. But when someone made a legitimate suggestion, it appeared to me that you were more interested in being right then removing the symptom.
Different releases will expose problems that may have been covered up in previous releases. Maybe SONAR 6 is drawing things differently than SONAR 5 and this is conflicting with you system and is showing up as glitches when the mouse moves. You've got to decide if you want the symptom to go away immediately or wait until SONAR changes it's behavior.
I say this because I've had situations where a piece of hardware no longer works on my system. It manifests as system instability. I had to make a choice. Hang on to the hardware, wait for new drivers or revert to a previous state. I've got a feeling that your problem could be with your Radeon Vidio card. It's not based on anything more than listening to others with Radeon cards and owning one myself. I'm getting some of the symptoms mentioned but changing the acceleration speed seems to affect it. I've changed out video cards before when problems occured and I'll likely do it again. In fact the last time I had a problem, a quick trip to a corner computer shop turned up a used dual head card in a used parts bin that only set me back a few bucks.
I just say this to save you a few headaches and some time. Give it a try if you haven't already. What could it hurt? Maybe it is IRQ problems? Why limit your solutions?