Best way to optimize G5 for pro recording use

[BradG]

I'm trying to sort out how to optimize my desktop Mac to be the fastest, leanest possible for it's main job. In this case it's a ProTools LE based DAW. Purists will tell you to not connect to the internet and probably not to install anything but your audio software.

What about a dedicated DAW user account (which would also probably need admin access, yes)? Would that be as lean as a naked hard drive, even if all kindsa other crap was installed in a general user account on the HD?

I'm considering a second Mac for "all else". Thing is that my main desktop will always have the most speed and biggest screen so it's way more productive for doing other stuff on, like graphics, web-surfing and... gulp, "Call of Duty".

*If multiple accounts are the way to go, what about Fast User Switching? So I can work on a session but quickly switch over to check email. Aside from RAM, will this use system resources?