DesertHermit
I was not successful in disabling speedstep. I looked all through my BIOS setup and didn't see anything resembling that or CPU temperature control. I'm on a Dell desktop. Any clues?

See Craig Anderton's post - it may not be a BIOS setting - it might be a windows power setting.

You can disable speed step on a per windows basis via a reg hack.. Google "core parking".

FWIW, it only takes one Core to hit a high consumption to get clicks and static. I've got a 4Core, 8thread Intel CPU that is fairly load-balanced between Cores. I do notice that the consumption doesn't stop even when Sonar's transport is stopped. Many times, freezing about half the tracks doesn't help as much as I'd like, but I noticed, it only takes one core to hit red before clicks and static occur, even if the other cores are much lower in CPU consumption.
 
So, I do find I'm having to freeze tracks more often lately than ever before, but it's not unbearable. It's just an extra step when I'm mixing.