I have a G4 450 tower, looking to upgrae to a 1.25Ghz chip from OWC..

Question: how big of a performance jump will I see in FCP going from 450 to 1.25? Most of the work done on this machine would be simple cuts, not many transitions or rendered effects. I have FCP 4...

Specs:
G4 450
1.25GB ram
60 GB hd
FW external drive
3chip dv cam
Os X 10.3.9

Kinda stupid question, of COURSE it'll be faster, but how much so? Benchmarks available?

I purchased a processor upgrade from OWC and I didn't notice a huge increase in performance in FCP but I have no benchmarks to prove that.

Personally I think processor upgrades are a poor value. A 450 is very slow so of course a 1.25ghz is better. I had to run FCP 4.5 on my powerbook for awhile during a recent trip. It's a 1ghz G4 with 1gb RAM. I had to tweak the RT extreme settings or it wanted to render everything. But after doing that I was pleasantly surprised at how well it ran. Of course you needed to render everything for final output, but I could work with multiple layers and see transitions in draft quality realtime.

Still, I think the money would be better spent on a new machine... just about anything in the current lineup will run circles around your 450.