At the moment none of the TCP tools out there (TCP Optimizer, DrTCP, etc...) will do jack squat on Vista. Vista takes care of all these settings automatically, well dynamically, and the jury is out on whether this is a hinderence or helpful...I hate it. I would rather have more control of MY system. However here are some commands you can run if you want to play with them, but from experience...you are better off sticking to what Microsoft feeds you as there was not a noticeable difference in performance after doing these settings.
You need to run and elevated command prompt. Click Start > All Programs > Accessories, right-click Command Prompt and Run as administrator, Allow it to have administrator privileges, otherwise these commands won't work.
To disable TCP/IP autotunning, in "Elevated" Command Prompt type:
netsh interface tcp set global autotuning=disabled
netsh interface tcp set global rss=disabled
To check that it is dsabled:
netsh interface tcp show global
To set back to the default Windows Vista behavior:
netsh interface tcp set global autotuning=normal
netsh interface tcp set global rss=enable
Manually setting the MTU:
Then type/copy & paste the following command:
netsh interface ipv4 set subinterface "Local Area Connection" mtu=1200 store=persistent
netsh interface ipv4 set subinterface "Wireless Network Connection" mtu=1200 store=persistent
Where xxxx = the MTU that you want. Rebooting isn't required. "Local Area Connection" is a common name for the interface if you use a NIC for connectivity. A wireless NIC may be called "Wireless Network Connection". If unsure, the network status icon by the clock will tell you.
If you have a router, ensure that the MTU is set to the MTU chosen here (refer to your router's manual).
Misc other commands:
netsh int tcp set global autotuninglevel=disabled
netsh int tcp set global autotuninglevel=Normal (To activate it again)
netsh int tcp set global autotuninglevel=experimental (crazy settings)
netsh interface tcp set global congestionprovider=ctcp
netsh interface tcp set global congestionprovider=none
netsh interface tcp set global ecncapability=enabled
“If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy”James Madison (American 4th US President (1809-17), and one of the founding fathers of his country. 1751-1836)