Comment 5 for bug 392089

I ran a few more tests on another PC and got some very interesting results.

The PC has an ASUS P5KPL-VM motherboard based on the Intel G31 chipset.

The results were the same for Kubuntu jaunty 64-bit and Kubuntu Jaunty 32-bit.

So it's not a problem of the hardware (unless it's the USB flash drive itself) and it's not a problem of the 64-bit version.

I also used the pci=routeirq and the pci=noacpi options on boot with no effect.

BUT... the problem does not appear in Hardy or Intrepid. It only appears in jaunty.

All tests were conducted after clean installs and with no updates.

The following are average times as reported from dd:

Hardy
avlass@avlass-desktop:~$ dd if=/dev/zero of=/media/disk/test-file bs=32
^C32215401+0 records in
32215401+0 records out
1030892832 bytes (1.0 GB) copied, 79.614 s, 12.9 MB/s

Intrepid
avlass@avlass-intrepid32:~$ dd if=/dev/zero of=/media/disk/test-file bs=32
^C112570144+0 records in
112570144+0 records out
3602244608 bytes (3.6 GB) copied, 315.495 s, 11.4 MB/s

Jaunty
avlass@avlass-kubuntu64:~$ dd if=/dev/zero of=/media/disk/test-file bs=32
^C63138817+0 records in
63138817+0 records out
2020442144 bytes (2.0 GB) copied, 311.369 s, 6.5 MB/s

I also attach the output of dstat for the Intrepid test