All of this basing scheduling performance on a bloated wannabe winamp makes as much sense as gauging car performance using a van. If this was a purely scheduling problem, then why do other players like alsaplayer and such not suck as bad as xmms when under the exact same priority and all? At least use something without a frontend so that you can limit the possibility that the programmers did something stupid like make decoding dependent on some update to the gui. xmms was coded first and foremost to look and work like winamp. Streamlined - even low latency performance was not a base goal.
The reality is that people use xmms, and whilst it may not be the greatest
program known to man, I don't believe it's *that* fundamentally screwed up
that it should skip under normal desktop loads. *Especially* if it worked
fine under 2.4 ;-)