Tue Sep 23 23:41:00 UTC 2008
Eduardo Grosclaude <eduardo.grosclaude at gmail.com>

Hi, I'm puzzled by an ASUS P5GC-MX/1333 with a WD320AAJS disk. My 5.2
DVD refused to see the hard disk. As the CD happened to have a bad MD5
sum, I assumed this was due to a bad burnt image.

Backed off to 5.1. Installation of 5.1 to /dev/sda went OK, then I
upgraded by yum to 5.2. But, at the next boot, the new kernel can't
see the disk. Only when BIOS IDE Setup is "compatible" I can boot the
new kernel. However, the disk shows up as /dev/hdc and performance is
noticeably slow. If I choose any other mode, nash complains that any
LVM groups can't be found and panics away.

I/O in general is terrible. Copying a CDROM to a file with dd renders
the machine nearly unusable.

The kernel provided in 5.1 can work in the BIOS IDE Setup
"enhanced/SATA" and performance is really good.  Hdparm when under the
current kernel says 3.51 MB/s buffered speed, whereas for the older
kernel it claims some 111+ MB/s.

I have updated the BIOS ROM to no avail. What am I missing? Is there
anything I can do except keep trying kernel updates?

Eduardo Grosclaude
Universidad Nacional del Comahue
Neuquen, Argentina