You can also try this as root. sysctl -w net.ipv4.tcp_window_scaling=0
. This is only a fix for certain sites that take a long time to load. If you are having problems with all (or most) sites this may not help (but won't hurt), and when you reboot it's gone so you need to do it again or put it in a startup script.
I don't remember who to thank for this