Performance issues and internet sharing

I'm adding a third PC, a new one, to my system at home.

Here is my current set up: two network cards in an old P200- one card to the LAN, one to the router, internet sharing software on this PC (sygate).

A P3-450 with a network card to the lan.

I'm adding a fast new PC (Athalon 1800+) with a network card, of course (to the LAN).

My question is, will I notice ANY internet sharing performance increase if I move the firewall to the P3-450 (and add the extra network card). Or is DSL traffic so slow anyway (relative to the P200) that it won't make any difference? I just don't want to endure the headache of moving anything I don't need to move if I don't have to. By the time I add the new PC, the oldest PC will only be used to archive files, and maybe continue to run the firewall.

Thoughts? Ideas?

(BTW-I don't run the firewall from the fastest PC since that is always at work as a DAW, and I try to run the DAW as lean as possible).

I've been to the mountain and didn't like what I saw.

You will not notice any different.