Is priority shared across all users? / Can you permanently - Microsoft Community

i'm user "a".  when go task manager, in "processes" tab, right click on process , change "set priority" level (e.g. "low" or "high"), "switch" user "b" still running, process still remember priority though i'm in b?  similarly, while i'm in b, if set priority "high", supersede running processes on other users less "high"?  (i have windows7 i'm guessing applies other versions).

i have older program renders fractal data can't have 2 simultaneous instances open within single user.  i found workaround creating multiple users can each run instance of program.  i have 4-core cpu (intel core i5 650), , run 4 cores 24/7 year long, i.e. have 4 users each running 1 version of program.  (i set affinity of each separate core, again right-clicking process, , doing "set affinity", e.g. user "a" may set affinity "cpu 0" , b, "cpu 1" , etc.)  but, want programs take immediate back-seat whatever else i'm doing in real-time.

aside, there good, safe way permanently set priority level whenever program starts, remembers level i've set?  i did bit of googling , there seem special 3rd-party programs this.  are trustworthy?  this page lists 5 tools this but it's hard trust nowadays.  do of legit?

i discovered dos code can change affinity when program starts.  you can add "/affinity 1" command line command executing program.  this worked me except starts program on same core ("cpu 0") if change number "1" "2" or "3".  am missing here?

thank help!!!! :-)

Windows / Windows 7 / Programs