I've done a bit of testing, and it doen't do it all the time, and it can change the priority of perl.exe sometimes. I run a mail, web, and lots of other things on a low end server (stupid, i know!) and i'm using process tamer to stabilise it a bit, and it's doing a good job - thanks!
The mailserver is using spamassassin to filter out spam and at midnight every day, it learns the days spam and genuine emails to its bayes database. This is done using perl, and i am unable the change the priority of this process and this is what Process Tamer also seems unable to do.
I only have the free version at the moment, so no gui, but i guess that it will also fail.
There must be something in the perl script which causes it to happen, but as i didn't write the script, i don't know!
Oh well, thanks for a nice program.