Very low writing speeds on RAID 0 with HPT374

[schorsch]

I am experiencing a very strange problem with extremely
low writing speeds, and I'd be really glad if anyone had
a solution for it:
As I noticed a significant decrease in system performance,
rendering video capture (which never was a problem before)
virtually impossible, I did some benchmarks and found a
ridiculous low writing speed.
To exclude software problems, I did a clean new install;
the following results were collected with only

- WinXP, SP2 & MS security updates
- Latest VIA Hyperion
- Latest ATI Catalyst
- HPT374 Driver 1.21.0.0 (10.03.2002)
*No other software installed*

System configuration:

AthlonXP 2600+
ATI Radeon 9700Pro
1 GB DDR333 RAM
Epox 8K9A3+ with HPT374
Latest Award Bios (13. Aug. 2004)
HPT374 Bios 1.24

4 Seagate ST3120026A (120GB/7200rpm/2MB), connected separately
to the 4 controller channels, configuered into 2 Stripesets
(Raid 0), 240 GB each, each partitioned evenly into 2 x 120GB.

"Performance Test 5.0" from PassMark gave me:

Sequential read 63,8 MB/s
Sequential write 2,8 MB/s *no typo!!*
Random seek + RW 3,9 MB/s *no typo!!*

Testing practically by copying a 4 GB file between both arrays,
in every direction (array1 -> array2 and array2 -> array1) I get
calculated speeds between 9 and 11 MB/s, what, as reading performance
seems ok must be limited by writing speed.

I did try to update the Windows driver for the HPT374, what resulted
in the controller beeing no longer recognized by the Highpoint
RAID-Management software, so, although controller & driver were
displayed correctly in the device manager I turned back to the 1.21
driver - performance was unchanged anyway.

Grateful for any ideas,

Schorsch