SCSI / SATA / FW800 test

[stevegalante]

Same thread in the Storage Subsystem section whene nobody answered... I'm on a G5 Dual 2.5G 6G RAM. ATTO UL3D with 3xIBM SCSI 10k 18G on one channel and 3x Seagate Cheetah 10k 36G on the other. I have two internal SATA drives (150G and 250G). I recently added an OWC Firewire 800 1.5Tb external drive (s) and I'm using the G5 FW800 port only (no FW400 devides). Together with the OWC package I received the Intech SpeedTools Utilities, which includes QuickBench, that I used to make some speed tests on the disks. Here's what I found (approximate results) for a transfer size of 1,024 Kbytes:

Sequential read:

SCSI 18 M/s
FW800 73 M/s
SATA 33 M/s

Sequential write:

SCSI 18 M/s
FW800 55 M/s
SATA 64 M/s

Random read:

SCSI 17 M/s
FW800 48 M/s
SATA 32 M/s

Random write:

SCSI 17 M/s
FW800 54 M/s
SATA 70 M/s

So obviously my question is : are these results 'normal' ? Is the SCSI bus limited by the configuration suggested by Digidesign for the ATTO UL3D card ? Just to make everything more complete here are the parameters of my ATTO card:

Selection Timeout 16ms
PCI burst Rate 128 bytes
Fallback Sync Rate 20 (10)
Sync Rate 160 DT