Firstly, you could have posted this in your other thread as well.
No need for a second one.
But anyway, if you are running Windows 2000 or XP, or even NT4 (I think), you can allocate it higher or lower priority by using the task manager. Press CTRL+ALT+DEL then select the process, right click, and go to Set Priority.
I'm not sure about Mac's, but I'm sure there would be a similar feature in the OS.
