Slimserver/Squeezebox does gapless all the time. And i've read at least 2 or 3 people now asking for an option NOT to do it. Can't please everyone.

The Gapless option in iTunes is also there to prevent it from cross-fading a gapless album. Considering how few albums are gapless, a manul option like this isn't such a bad thing. LAME can also set a gapless tag which some software should pick up (not sure if iTunes picks this up). iTunes also does some gapless analysis, but I have no idea what it's actually checking.

A large library should not pose much pf a problem to a P3 at 550MHz. Not for music playback nor database access from a connected Squeezebox.

Where you will notice slow performance (that's relative) is in the web interface. I'm one of the people talking about slow web server performance in the Slim forums at this moment. I even started a thread called "Slimserver wants a fast machine"

There are people running pretty large databases on NAS devices using imbedded processors which are dead slow compared to any P3.

I have about 12000 tracks right now and have used slimserver on a G4 dual 533MHz and currently on a Mac mini Core Duo 1.6GHz.

I have around 22000 tracks on a P4 1.7 with 768mb ram, web interface is hugely slow sometimes but in general it's responsive and fast (as long as you don't ask it to shuffel play the whole music library, thanks for the tip on "random mix" guys).