Slowness with new pc

[Stian Jordet <liste@jordet.net>]

Hi!

This fall I built myself a new computer. It's a dual cpu quad core xeon
(E5405) on a Supermicro X7DWA-N motherboard. It has 8GB 800mhz ram, and
a Supermicro AOC-USAS-S8iR RAID SAS controller, with a pair of Fujitsu
MBA3073RC disks in raid 0. Should be pretty fast, but it isn't. In daily
use it feels just about the same as my old Dual P3 1ghz with a single
SCSI disk. Has to wait a couple of seconds before the gnome menu appears
after I've clicked on it, for instance. But with operations involving
heavy disk use, it's extremely slow! For instance, unpacking the bzipped
2.6.27.6 kernel takes 6:40 minutes, while compiling it takes a mere
5:13. I thought I had a hardware problem (still not ruling that out), so
I tried to install Vista, and then everything was blazingly fast. I have
no clue where to look, but a static benchmark like hdparm gives me a
throughput of 235MB/s on the raid 0 array. Could it be
filesystem-related? I'm using XFS (always have)... 

Please cc me on any replies.

Regards,
Stian