I have a PPC G4 sawtooth and I have been contemplating upgrading to 10.5 my current specs are: 400MHz cpu 2 hard drives: 120G HD 10G HD 1.5G of RAM will it benifit me to purchase this:http://eshop.macsales.com/item/Other%20World%20Computing/MEG42M1200/ as 400MHz is awfully slow?