Search for RunPrio on Google. It allows you to launch programs at different priorities plus it's very small in size too:)
@RB, I didn't know that. Thanks for the info. I though you updated it for Basic 2.69, but now I see that you last updated for SP 2.67.00.27.
Remember that mpeg2dec is a memory hog also, so when you use CCE with an avisynth script using mpeg2dec the cumulative memory usage is heavy.