When it is possible it is done in the X configuration. But all of this
is moot for m, as she has a ThinkPad 600E that runs at AGP 1X already.
And m, that's a NeoMagic 2200 chipset in your 600E (OK, NeoMagic calls
it a MagicMedia 256AV, but X calls it a neo2200).
I have no problems running a cheap Griffin iMic USB audio device on my
600E, and USB is sharing its interrupt with eth0. I'm running a
2.4.21-pre3-ac2 kernel on Debian stable, no low-latency patches.