Hi there, I'm running a centos 5.2 (with a centos 5.3 kernel) on a box with a samsung 1To green edition, and this disk looks a bit slow to me and it's not recognized by hdparm : # hdparm -iI /dev/sda /dev/sda: HDIO_GET_IDENTITY failed: Invalid argument HDIO_DRIVE_CMD(identify) failed: Invalid argument # hdparm -tT /dev/sda /dev/sda: Timing cached reads: 2252 MB in 2.00 seconds = 1125.57 MB/sec Timing buffered disk reads: 94 MB in 3.05 seconds = 30.81 MB/sec I've got a samsung 640go on my desktop running ubuntu (kernel 2.6.27-11), hdparm -iI is working and benchmark is a lot better : $ sudo hdparm -tT /dev/sda /dev/sda: Timing cached reads: 2392 MB in 2.00 seconds = 1196.00 MB/sec Timing buffered disk reads: 226 MB in 3.02 seconds = 74.81 MB/sec the green HD is a 5400rpm, though the other one is 7400rpm, but a factor 2 in performance between them looks very strange to me. As the green 1 To disk is not identified by hdparm I think it's not configured properly. Any hint to make my 1To disk flying like the other one ? :) cheers, David