Maxed out power supply

[Len McGrandle]

I have a G4500 AGP and have added the following to it:
-Superdrive
-Firewire driven video system (Formac)
-Ultra Wide SCSI card
-ATI 8500 card
-768 megs RAM

I am considering a processor upgrade to 1.2 gigahertz for video 
processing

At what point to I place too much demand on the power supply?  Will I 
not have an overheating problem?  I don't see much about these problems 
on sites such as Accelerate Your Mac.  Anyone have experience or 
knowledge of this?

Len