U160 Scsi slow. Why?

My puter went pop the other day.
So, I took the chance and installed two u320 drives using raid 0 on a u160 LSI perc3/sc megaraid 475 series controller. I managed to get some windows 2000 drivers (xp ones didnt work) and installed windows which now works fine.

The problem is, I've benchmarked this setup and the results are not impressive. I'm getting about 55-60mb/sec which I think is far too low.
My seagate ata100 drive manages 55 easily and raid 0+1 ata150 setups on other machines I've built in the past have managed at least 100mb/sec.

Anyone have any ideas why its not getting more than 60mb/sec?

(heres the drives I'm using. http://www.novatech.co.uk/novatech/specpage.html?IOM-8B073L )

Thanks in advance.

 

All my computers are scsi setups, so I might be able to make a decent
guess here. You are squeezing a u320 into a u160 pipeline and also,
it is running off of a card which isn't always as good as onboard.
You would probably see quite a boost in burst rate if you ran a 320 card.
But my advice is to not worry about it though. At the end of the day
you don't push a hd to it's limits very often. Not only that, but
burst rate is only one of many measuring sticks that the scsi drives
do well in.
My main comp is a Tyan K7 thunder mobo, with two MP2200 proc's and
four Seagate 10,000 rpm scsi drives, and it runs
so smoothly that I wouldn't care what the burst rate was.
And as a plus there is that fantastic Rollys Royce build quality
in scsi drives that the ata drives just don't match.
If it's important enough of an issue to you, then pony up the bucks
for a U320 Adaptec card.

 

One other point to make: Adaptec cards play extremely well with XP.
I have two 50 pin Adaptec cards as well as a U320 Adaptec
running a 15,000 rpm scsi drive. All of them loaded right from
the install.

 

Thanks for the reply.

I think I'll probably give up sell the bits and go for sata. I've come to the conclusion that either raid 0 is no good on scsi where as raid 5 is far better or my pci bus is flooded with other devices chattering. Theres no easy way round either of those issues. A U320 card may help a little but I'm not even getting u160 speeds out of the current controller so I cant see a U320 card doing much more.