So as you can probably see by the title of this post, I have managed to get my old iMac G4 800mhz with 758mb ram to run Leopard 10.5.8, and I have a few notes that may help you along the way.
1) Keep it simple.
Don't mess around in open firmware, just download LeopardAssist (in downloads page) which fakes the clock speed and lets leopard install. **Please note that after this app is run, you MUST boot into the install DVD, as if it is rebooted more than once, the process is undone.**
2) ***Don't*** upgrade the OS.
Seriously, this was my major problem. I always tried to upgrade from Tiger 10.4 to Leopard 10.5, and it would install, but on first boot, kernel panicked constantly.
A fresh install will be faster, and also, works.. no kernel panics, its really smooth. Just make sure all files you want to keep are on a separate drive or storage medium.
3) Let it settle.
When I first got to the Leopard desktop, I was horrified at the performance, and I really regretted upgrading. I started reaching for the Tiger install DVD. Then I remembered - Spotlight was using tonnes of system resources, indexing the system. Waiting for it to finish or disabling it completely (google that) will greatly increase performance, so don't go running for Tiger until you've tried Leopard for a few days.
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