I'm currently using a G4 1gig dual processor, how much ram do you think I'll need for it to run with no probs?

I don't use logic, but I can tell you this:

The amount of RAM you need to run any audio editor "comfortably" depends on a few things. RAM is directly proportional to successful real-time playback. The more RAM you have, the more likely your editor will not skip, crackle, or freeze. You might be able to get away with insufficient RAM by consistently rendering to file, but thats terribly inefficient.

It also depends on the complexity of any samples you're using. Samples are allocated directly into RAM and remain there as long as they are used in playback. The majority of memory is saturated by samples, not the controller.

I'd say at LEAST 1gig of RAM if you're going to be doing any serious audio work. I have 2gigs and still run into problems from time to time.

A desktop RAM monitor widget has proven very helpful to me for memory management purposes.

Hope this helps.

Under OS X, 512 MB is a minimum to have the OS working somewhat smoothly, 768 MB and it breathes, you can run Office

Around 1 GB starts to be ok as long as you don't use much virtual instruments, samplers, plug-ins, then sky is the limit. as Xaosai said, between 1 and 2GB you'll do the job most of the time, but the better is the enemy of good as we say in French.

Thanks a lot

I have that dual 1GHz G4 PowerMac and use Logic Pro 7.1. I've got 1.75Gb RAM in mine. It came with 256 (what were they thinking???) and I've added 1.5Gb extra since. Works pretty smoothly. 2Gb is the max in this computer. I still have to freeze virtual instruments if I've got too many running in the same track, but I don't mind - necessity is the mother of invention and all that.