On Wednesday, June 25, 2014 1:16:11 AM UTC+8, Paul wrote:

It does sound to me like PIO mode (4 to 7MB/sec), so you're
looking in the right area. You would think of
all utilities, hdparm would know what it was talking
about.

If there is a dmesg, see what happens to the drive when it
is detected, and whether any anomalies are noted.


I know that when Win2000/XP counted disk errors, they ratcheted the speed
down until you ended up with PIO. I don't know if linux kernels do the same.
I'll put it down to a flaky interface, and use a SATA disk instead to get
it going.