Processor upgrade question

[psullivan at knology.net]

Wanting to do some home movies of the kids & VHS conversions on a budget. I'm building a Sawtooth G4 system. Question is:

I have access to a G4 dual 500 CPU for $215. The alternative is the G4 800 processors in the $250 range. Which processor would be better?

My mobo has a Uni-N 7 chip so the DP will work. I have a spanking new copy FCE for $99, a side benefit of buying my dad a new emac for doing 
iChat AV together :-) I will be using FCE or iMovie.