Hello, i'm running kubuntu jaunty and whenever i try to copy a few gigabytes to my external backup drive, the computer slows down. Stuff like switching from firefox to thunderbird take about 15 seconds instead of half a second. Everything is just super slow.

Looking at my processes (top), the cpu is pretty much idle.

As soon as the usb transfer stops the computer is fine again. I've tried using nautilus and dolphin and both slow the computer down. I've tried gnome and kde and both are the same.

Even typing in the command line is slow.

The computer is a dell P4, 2.8Ghz, with 3gb of ram and a 250gb seagate hard drive internally. I've got several external drives and they're all slow. All drives except my boot partition are xfs. The boot partition is ext3.

-Thanks for any help provided.

Oh and i'm talking about just doing a transfer. I'm not running a program that is archiving and transfering at the same time, as that would use a lot of cpu and a slowdown would be understandable.

Possibly a buggy driver for the USB controller you have. Do you get any errors or strange messages in the system logs during the transfer? Do the boot messages mention anything about USB while the system is starting? Kubuntu uses a bootsplash so you wouldn't see them normally, but you can check them after the machine starts with a command like "dmesg | grep usb".

I've got a similar issue with my laptop. If I use the CDRW/DVD drive and the USB at the same time, the mouse updates every 3 seconds or so and it just becomes unusable until it finishes. I don't have this issue with any other computer with the same distro (to some extent) installed. I was going to recommend more RAM, but at 3GB, you've got 3x's more than my best at the moment. Is this a laptop that you're using?

Here is a dmesg | grep usb printout:

What log would i check? Also, the transfer speeds are pretty decent, (20 megabytes per second or so) it's just that the whole computer slows down to a halt, even though top reports the cpu as nearly idle.

I know this is a really old forum post but I think I found a solution.

I was experiencing the same kind of behavior with the mouse updating every 3 seconds during an rsync to a 'generic' microSD card from local hard disk and found that I had to manually throttle the transfer speed to --bwlimit=2048 or 2 MB/s. Hope this helps some people.