Enocding speed to mpeg-2

[macbos]

I'am thinking about buying a G5, i now us a Emac 1 Ghz with 1 Gig ram, to encode DV/divx to mpeg-2 it takes about 4/5 housrs to encode one hour film to mpeg-2 (using ffmpeg), howlong does that takes on a G5 single or dual????

[sdm]

on my work computer (dual 1.8) ghz, ffmpeg takes about 1.5x-2x realtime.
I'm ussually doing other work though, so my answer is abit off.