is G4 64 bit

It's a pity, but only the G5 is 64 bit. G4 is 32...

 

If you're not going to be using more than 4 GiB of virtual memory, you don't care if it's 32-bit only, just how fast it is.

 

No G4 CPU for the moment is 64Bit but the future we don't know.....As said if you don't need more than 4GB RAM or other heavy 64Bit apps then look at FSB and Core speeds

 

You have to look at benchmarks, not MHz.

 

No. It does have a 128-bit vector processing unit, though. It's still quite a neat piece of technology.