Do you have a lot of traffic on your LAN? If you unplug the win PC and one ubuntu PC, do things speed up on the remaining PC?
Is someone stealing bandwidth from your wireless connection?
Do you have IPV6 enabled? If so, you could try disabling it (you'll need to make these entries in
/etc/modprobe.d/aliases
Code:
alias net-pf-10 off
alias ipv6 off
then reboot.)
If you are using firefox, you can turn off firefox trying to use IPV6 by going to
in the address bar, and then
IPV6 in the search box then set
network.dns.disableIPv6 to
true
Any better?