Jerky I/O scheduling

[Ville Vainio]

I've been wondering whether there is something "wrong" with i/o
scheduling of Ubuntu. I have a SiI 3112 sata controller with Seagata
Barracudda drive (abit KD7S motherboard, which is a Via Kt400 board.
Athlon Xp 2400+, 512Mb ram), and when copying large amounts of data
(to/from other disk, from network to the disk) the computer starts to
feel jerky. I'm using Nautilus to do the copying. This shouldn't happen
w/ 2.6 series kernels, and I don't recall experience like this w/ other
distros. Music stutters a lot (becomes unlistenable), mouse moves
erratically, etc. "top" doesn't display any process as eating up all the
performance - xfree86 is typically eating up most of the performance,
and it's typically only something like 30-40%.

I wonder if anyone else has been having similar problems, and whether
there is something I could do about it.