Here is a quick little AHK script to automagically set SE5 to "Below Normal" priority whenever it is detected.
The script then waits for SE5 to exit before looking for a new instance of SE5 to set, so it does not waste CPU time.
http://imagemodserver.mine.nu/other/...rioritizer.zip
Source code (302 bytes), plus a compiled exe version (196kb) are both included.
For everybody on a single-processor system, this should help immensely.