Logic Pro 9 (and then Logic Express 9) indeed works perfectly on a PowerPC mac (universal binary application). Moreover it seems performing ways better than Logic 8 (by using more efficiently distributed load accross CPU cores), so running it on a G4 shouldn’t be a problem :
For the record, LP9 is up and running on my G5 Quad. While I’ve yet to fully test functionality or Mainstage 2 fort hat matter, I can say that the upgrade process ran smoothly.
I’m editing a large project at the moment and I’ve not yet run into any issues. One thing I can say is that all 4 processors in my Quad seem to be better utilized than under LP8. Load looks very evenly distributed.
PPC and Logic 9 works…trust me. I’m running it right now– and I’ve worked on three large projects just today.
In terms of MASSIVE performance improvements; I’m a bit stumped. My G5 Quad is running at about half CPU in a plugin intensive session containing about 46 tracks (32 MIDI). Disk I/O load is also about nill. Memory is at about 75% utilization.
UPDATE : as stated through below links, Logic Express is Intel binary only starting 9.1.1 update (the updates won’t apply on PowerPC).