Comment 72 for bug 417757

I have the same problem with 2 desktops and a laptop. I've tried the laptop wirelessly on 3 different networks and the severe slowdown continues. The workaround below fixes the slowdown by disabling IPv6 on bootup (it's worked on all 3 computers):

start a Terminal session and type:

gksu gedit /etc/default/grub ....then change

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 quiet splash"

then

sudo update-grub

Reboot and network speed should be back to normal.

I hope that a fix for this disconcerting bug is provided ASAP. Thanks.