IDEA: Set non-focused processes low/below normal priority

[tmpusr]

Idle/low priority non-focused processes, except system processes, though idling most of them is ok - it seems only csrss.exe and System need to remain normal or higher unless you want UI slowdowns and audio/video dropouts. Also as groups: when any of X, Y, or Z are focused, all are non-idle.
Each process can have its focused and unfocused priority set; you could have non-focused at a higher priority. You need to be able to set all process priorities permanently. Prio http://www.prnwatch.com/download.html helps but doesn't do system processes.

See also suspending processes
http://www.donationcoder.com/forum/index.php?topic=16746.0

[tmpusr]

Almost a solution:
Setting every process to idle and running one small exe that raises focused process priority
http://www.lockergnome.com/windows/2008/02/25/actual-booster-31/