> my 500MHz 256MB Linux box running xmms also skips when I scroll
> netscape slowly with the mouse.

have you tried making xmms suid root, and setting the "use realtime
priority when available" option?  here's what the xmms docs
(http://www.xmms.org/documentation.html#section-1.12) say about it:

"Use Realtime priority when available. This works only if xmms is runned
by root or is setuid as root. This will get xmms the cpu it needs all
the time and it won't be easy to get it to skip.. You won't be able to
use the diskwriter plugin with this option enabled."

not the best grammar in that description, but the feature works well.
xmms almost never skips in my PII-233 w/160MB (and rarely did it skip
when i was using a P-233 w/ 64MB).  only when i'm doing disk-intensive
stuff like creating iso images or copying huge files...

hope this helps.

phase