hdparm error

Hello,
I Installed my amd64 box tonight and the ftp installation went fine
(except that I couldn't select some contrib noarch packages because of
some missing dependencies).

I now have a message I don't like when running hdparm :
[root@coin pterjan]# hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   3732 MB in  2.00 seconds = 1865.35 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate
ioctl for device
 Timing buffered disk reads:  176 MB in  3.02 seconds =  58.23 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate
ioctl for device
[root@coin pterjan]# hdparm -tT /dev/sdb

/dev/sdb:
 Timing cached reads:   3756 MB in  2.00 seconds = 1878.29 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate
ioctl for device
 Timing buffered disk reads:  176 MB in  3.02 seconds =  58.27 MB/sec
HDIO_DRIVE_CMD(null) (wait for flush complete) failed: Inappropriate
ioctl for device

The motherbord is an ASUS A8N SLI Deluxe and the controller I currently use is :
sata_nv         : nVidia Corporation|CK804 Serial ATA Controller [STORAGE_IDE]