This is fascinating. I tried the Terminal trick too. No difference in CPU use or performance with X 10.1.5. The Terminal window shows a long list of what seem to be error messages regarding Cookies, GUIMediator, MacEventHandler, FileOutputStream, etc.

I'm having kernel panics like Janet with LW 2.8.5 which I'll bring up in a new thread. It seems unrelated to running other programs however.

Tom