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ML350 Embedded SATA operates in PIO mode

Domenic DeFrancesco
Occasional Visitor

ML350 Embedded SATA operates in PIO mode

I setup an ML350 G5 with two mirrorred SAS drives and Windows 2003 SP2 (HP branded). Works fine. I added a 500GB SATA drive to the embedded SATA connector located just below the floppy connector on the mother board. The idea here is to have a large non Raid storage for backup and non critical data. Windows 2003 discovers device and installed the standard ATAPI driver. However, the Microsoft driver reverts to PIO mode. Read and write speeds to the SATA drive are very low, and CPU utilization is about 26% during file copies.

As a test, I created a folder with about 250 files totalling 1 Gigabyte. Copying from one partition on the SAS drives to another partition on the SAS drives took 38 seconds wiht only 4% CPU utilization. Copying the same files from the SAS drive to the SATA drive took 270 seconds with 26% CPU utilization! (It's 26% because it's a quad core cpu, and one core was spending 100% of it time on the file copy.) Copying from the SAS drive to an consumer grade cheap USB drive took 44 seconds.

There are a number of KB articles from Microsoft that address the atapi.sys driver operating in PIO mode. Non of these articles resolved the ML350 G5 issue.

It appears to me that the SATA chip set in this machine emulates an IDE port for compatibility reasons. The Microsoft driver loads, but can not use the DMA modes. I would think that there would be an appropriate driver for this SATA port that allows it to perform an normal SATA type speeds.

Anyone have any ideas.

HP support was on no help and has "archived" the case. Thanks....

Domenic