Trouble Installing OS X Leopard 10.5.6

[dswday]

can't operate iPod classic on existing OS X 10.4.11. Called Apple customer service and was told i needed Leopard. When attempting to install, message is: can't install OS X on this computer.
My computer is:
Machine Name: Power Mac G4
Machine Model: PowerMac3,4
CPU Type: PowerPC G4 (11.3)
Number Of CPUs: 1
CPU Speed: 533 MHz
L2 Cache (per CPU): 1 MB
Memory: 640 MB
Bus Speed: 133 MHz
Boot ROM Version: 4.1.8f5
I have 38.34 GB capacity and 6.76 available.
Can anything be done? Do I need 10.5 before updating to 10.5.6? Help.

 

[DeltaMac]

System requirements for installing Leopard show that you need at least an 867 MHz G4.
http://support.apple.com/kb/HT3759
Although a small detail, you also don't have enough free space on your hard drive. Leopard installer needs a minimum of 9 GB free.
The processor speed, unfortunately, is the main block for you.
If you can free up the hard drive space, there is a solution:
http://www.macupdate.com/app/mac/26562/leopardassist/
This utility fakes the installer into seeing a faster processor.

Another recommendation if you want to try this: Install more memory.
Your PowerMac can have up to 3 x 512 MB of PC-133 SDRAM for a maximum of 1.5 GB
You can expect very poor performance with only 640MB of memory.