Comment 19 for bug 216878

My situation might be related to this bug:

I bought a Thinkpad T61 in last October. I erased Vista and installed Ubuntu 8.7 and later upgraded to 8.10. The disk speed seemed slow. I tried the following command to test the real read speed:

$ date; cp a_100_MB_file /dev/null; date;

The copying takes about 20 seconds. So the speed is about 5MB/sec.

But when I try to use hdparm to test the read speed, the result is like this:

$ sudo hdparm -t /dev/sda

/dev/sda:
Timing buffered disk reads: 130 MB in 3.03 seconds = 42.84 MB/sec

Can anybody tell me why the real read speed is far from the 42.84MB/sec?