What kind of Operating System for PowerBook G4?

With such little info, I’ll give you the best information I can. What I’m telling you will be limited in scope, but it should still prove helpful.

Most PowerBook G4's will run Leopard, but it’s not ideal with less then 2GB of RAM as it’s prone to RAM related performance issues. Tiger (10.4) is better on RAM limited systems, but you will also have to deal with crappier software compatibility. Yes, 10.5 (Leopard) works but not well.

For models that are RAM limited (1GB or less), use Tiger for your own sanity. The performance tradeoff is significant and you will be able to tell. Leopard only runs well with 2GB or more, so it only makes sense to deal with the tradeoff if you have 10.5 only software.

The maximum OS you can run is Leopard (10.5.8), however I recommend running Tiger (10.4.11), because Leopard would be a real drag and incredibly slow, with bad performance.

I would also suggest maxing out the RAM, which you can do at 1152MB, however due to slot configuration, the best you can do is settle at 1.0 GB (1000 or 1024 MB), you could put something in the other slot, but it would not be detected, you can get this stick here.

As for the OS, you can get it pretty easily on eBay or Amazon, such as right here, however if you google around there are plenty of Macintosh sites and sellers that have whole archives of every install Disk and will sell to you for a good price.

I have book...upgraded ram from 256 to 1.gig of ram...replace the original 40'

hd to a 160..and jumped it from Tiger..to Leopard..10.5.8

runs much better...than it ever did...and for a powerbook that's 8 yrs old,

that's great..and it still turns heads...

I once had a PowerBook Titanium 867 with 1 gig RAM and it ran beatifully with Leopard.

According to Apple-history.com. the max is OSX 10.5.8

If you have a slow PowerBook, I suggest you use OS X 10.4.11, as it is the fastest with older mac's. If your mac has more than 2 gb of ram, then it is probaly OK to upgrade. If you are simply upgrading to get a better dock and theme, you should get ShapeShifter and ClearDock at: http://shapeshifter.en.softonic.com/mac or http://unsanity.com/haxies/shapeshifter

I have been using Leopard on my 12'' pb with maxed out 1+256GB ram. Did not go with Tiger due to the lack of time machine support. Everything is responsive. I am missing a good browser tough. I tried all G4-optimized firefox versions, but none of them can beat camino and Opera. Overall it makes a great travel laptop.

I also tried yellowdog and ubuntu, but they both lacked HW support. I would love to have linux on this machine, but it will never happen, I am afraid.

I say Leopard some linux distros may also work

Mac OS X 10.5.8 Leopard is the maximum OS for all PowerPC machines with the G4 and G5 processors.