PCI-X/Ultra320/RAID tuning problem?

[Dave Zarzycki]

I have the following setup, which is performing below my expectations.
I was wondering if any of the list subscribers could provide any tuning
tips:

Red Hat Linux 9
Tyan Thunder i7501 Pro (S2721-533) motherboard
2GB RAM
8 Ultra320 Seagate 15k.3 drives, 4 on each Ultra320 channel
no additional PCI/PCI-X devices installed

dmesg:   http://zarzycki.org/~dave/dmesg

lspci -vvv:   http://zarzycki.org/~dave/lspci-vv.out

These lines in the dmesg output seem troubling:

aic79xx: PCI4:2:1 MEM region 0x0 unavailable. Cannot memory map device.
aic79xx: PCI4:2:0 MEM region 0x0 unavailable. Cannot memory map device.

I seem to be topping out at 200 to 255MB/s depending on the setup
(messured with hdparm -t and dd), while each drive is capable of 72MB/s.
Dual Ultra320 with PCI-X should do better than this, right? I'd estimate
500+ MB/s given this setup. Am I being unreasonable?

Thanks for any help.

davez

-- 
Dave Zarzycki
http://zarzycki.org/~dave/