This is in repsonse to this older message which I can not post a direct reply to : http://miataru.computing.net/beos/wwwboard/forum/1055.html
I have a Mac 9500MP a dual 180mhz PPC with 208 Meg of RAM. Performance is good but nowhere near the performance of a Pentium. I never ran BeOS with an old Mac upgraded to a G3 or G4 CPU. I know you can do it but I never upgraded a CPU on any of my Macs.
Like the previous posting stated there are far fewer applications on the PPC side than on the X86. Your biggest loss is in the Web Browsers. Under PPC you only have Net+ and that's it, no Mozilla, Firebird, or Opera. Even if you did many of the older Macs (603 or 604) out there would probably not be able to handle it CPU wise.
I also run BeOS on a Mac 8500-120 with 64 Meg RAM and a Mac 4400-200 with 48 Meg of RAM. Only the 9500MP with dual CPUs shows any signs of life as far as performance goes. I know the extra RAM helps but you are dealing with very old hardware with slow system buses. The 9500MP has a 45mhz bus while the 8500 and 4400 have a 40mhz bus. Plus depending on the CPU some 603s and 604s have little to no L1 or L2 cache. Compound that with slower SCSI, RAM Speed and built in non accelorated graphics cards of the 8500 and 4400 things are not too pretty. It's just old hardware plain and simple.
I also run BeOS R5.03 on my Sony Vaio J-150 a 800mhz AMD Duron with 384 Meg of RAM and there is just no comparison in speed between the 9500MP and the Sony. The Sony just plain smokes the Mac.
Don't get me wrong I love my 9500MP and run OS 9.22, OSX 10.1.3, BeOS R5.03, OSX Server 1.1 (aka Rhapsody 5.5) and Win98 via an Orange Micro card under OS9.22. Though this machine is no longer my main machine it still does get some use. BeOS on an old Mac adds more use/life to the system.