Comment 114 for bug 197762

I did a bunch of tests. First of all, I'm attaching the output of:

cat /proc/version_signature
dmesg
sudo lspci -vvnn
sudo lsusb -vv

I used Ubuntu Jaunty kernel "2.6.28-9-generic", except for the log of "lsusb", which was acquired when the system was running under 2.6.29-rc7, vanilla, from kernel.org.

The system is the latest Kubuntu Jaunty alpha with updates as of 10 March 2009; architecture: AMD64.
I did the tests running KDE 4.2.1-0ubuntu5 and used the automatic "pop-up" feature to mount a 16-GiB USB pendrive specified for a minimum throughput of approx. 14 MiB/sec.

These are my observations:

Copying large files (i.e. approx. 8 GiB) from high-performance harddisk to the USB drive using
_Microsoft Windows XP SP2_, the above-all average transfer speed is 13...14 MiB/sec. This is always reproducible.

Using my Ubuntu system:
When _copying large files using KDE_, after the first 3GiB or so, the transfer rate drops from the initial 14 MiB/sec to an average of about 5.5 MiB/sec. The indicated speed on the progress window fluctuates between a few kiB/sec and full speed.

Using the _command line_ and timing the following commands using a shellscript yields /slightly higher/ average transfer speeds, approx. 7 MiB/sec.

Ubuntu kernel 2.6.28-9-generic and a custom 2.6.29-rc7: No difference.

Conclusion: Using Ubuntu, the transfer speed is always less than half the speed than under MS Windows XP.

I did at least 20 tests with different file sizes, file systems on the pendrive (VFAT, EXT2, fuse NTFS3G NTFS)