http://www.sevenforums.com/tutorials/94721-mtu-limit-test-change-your-connection-s-mtu-limit.html
http://otvety.google.ru/otvety/thread?tid=127df94ee6237ae0
netsh interface ipv4 show subinterfaces
ping google.com -f -l 1472
You will need to add 28 back on to the value for IP/ICMP overheads, so if 1462 is successful, then 1490 is your MTU limit.
netsh interface ipv4 set subinterface "Беспроводное сетевое соединение" mtu=1489 store=persistent