Murz, thanks! Change queue to noop solve my problem without reboot.
Now I have stable 8-9 Mbyte/sec with SD class 6 card.
This trouble affected my desktop (64 bit) and notebook (32 bit) Ubuntu 9.10
installs.
--
file transfers on USB flash key (pendrive) are slowing down with time
Update
After 10 Gbyte transfer to sd card speed is down again. Scheduler fix is not
enought for me.
May be it would help for someone -
http://ubuntuforums.org/showpost.php?p=8653721postcount=29
yes its fixed, but not in the 2.6.31 kernel branch. I experienced the same
problem you described
