Hey Aaron,
I'm currently running Xlobby on a P3 733 with 396Megs of Ram. I'm using a Soundblaster live 5.1 and the KXDrivers along with 4 instances of Winamp (Version 2.94). It runs multizoning pretty smooth. The only problem I could forsee with your hardware, is that you will have a problem with synching all zones. My setup works for about a song, then it starts to go out of synch when using Steven's Xlobby synch command. What I have done is create my own command event, taking advantage of the KXDrivers, and that works rather well. The other thing about that computer is that it is the main workhorse computer currently, so there is alot of extra stuff running in the background. I'm slowly putting together a 1.7Gig P4 strictly for a multizoning server. Things may be even better then.
Check out towards the end of this post:
http://www.xlobby.com/forum/viewtopic.php?t=3931
for what people are now starting to realize it could be a hardware constraint. Disregard its title as it appears to be turning into a syching problem as opposed to a crash issue now.
Also check out this post:
http://www.xlobby.com/forum/viewtopic.php?t=3714
which Steven, in the end, links to the post above.
Hope this was helpful.
David