VERY RECENTLY issued patch for WinXP USB…Fixes problem and speeds USB up considerably…This must be the VISTA version of the drivers since it is still a HOTFIX. Rumour has it that they’ll be releasing a Service Pack for WinXP (SP3) with VISTA-like updates
https://www.microsoft.com/en-us/download/
Run the executable in the UNPACKED directory (only on Windows XP – Any variant: Home, Pro, etc)….reboot..
I suspect that the USB adapters will work better when they share the bus with other USB devices (like portable drives)…
Problem report to which the HotFIX was the answer…
http://support.microsoft.com/kb/908673/en-us
The problems have been reported going back three years….A fairly deep look at it is here:
Generally, the problem has been known as the “delayed write” problem on USB and it causes an inordinate amount of pain and suffering such as corrupted disks….Not exactly what you have in mind as you try to use an external drive to backup your internal one…Microsoft did nothing about this for at least four years.