Upon looking on this site
They have the 800MHz G4 upgrade and the 1.0GHz upgrade both for the same price. I was told that the 1.0GHz reduces the bus speed from 100MHz to 66MHz in order to retain stability, while the 800MHz keeps it at 100MHz.
Now my question is will the 1.0GHz speed compensate for the reduced bus speed? I noticed at looking at the benchmark tests, that the 1.0GHz has a much better rating over the 800MHz, so is this a rumor or what?
Here are some benchmark numbers -