According to a recently unearthed Apple Knowledge Base Article, you PowerPCers out there aren’t getting the full iPhoto ’09 love when it comes to transitions effects. G4 users only get Ken Burns and Classic. G5 users get Classic, Ken Burns, Scrapbook, Sliding Panels. Intel owners get the whole nine.
The number of slideshow themes available in iPhoto ’09 depends on your Mac’s processor and, in some cases, available vRAM:
Intel-based Mac computers, PowerPC G5 with more than 64MB of vRAM: All iPhoto ’09 slideshow themes are available, as in the image below.
PowerPC G5 with less than 64MB of vRAM: Only Classic, Ken Burns, Scrapbook, Sliding Panels are availabe.
PowerPC G4: Classic and Ken Burns are available.