Does SMP make a difference in encoding?

[Qs]

Does anyone know of an encoding program that's multithreaded and can utilize two cpus? Has anyone tried this? What kind of speed difference is there in contrast to a single cpu system?

tia :D

[Acaila]

Here's what I said on that subject a little while ago:
http://forum.doom9.org/showthread.php?s=&threadid=27038

[Prosper]

Yah it makes a difference, but not as much as you might expect.
The major advantage is being able to run everything at normal priority and still being able to _use_ the PC for other stuff at the same time. I usually hit 80% usage using avisynth->vdub method.