Sunday, June 22, 2008

Increase Multithread Download Speed by Disable Vista Auto Tuning on TCP/IP

In Windows Vista, Microsoft incorporates new TCP/IP stack which features Auto Tuning capability. The Auto Tuning function able to adjust and optimize TCP/IP connection based on network utilization in order to increase the transfer rate throughput. In theory the new stack suppose to do so, however, in practical, Auto Tuning feature may not work correctly to bring better performance for network downloading and web surfing.

Other than the problems mentioned previously, Auto Tuning may also cause reduce the rate of establishing network connection, especially when using third-party driver for the network card. Other possible problems are Windows Live Messenger slow sign in process or unable to login, slow speed when viewing shared resources in LAN environment, or slow download speed when using multi-thread multiple-concurrent-connection programs such as FlashGet, BT clients such as uTorrent, BitComet and etc comparing with the download speed possible to get in WinXP.

All these symptoms may not caused by “Auto Tuning”, however, trying to disable Auto Tuning on TCP/IP in Vista to verify if the problems have been solved is a good way to ensure that it’s not the culprit.

Disable Receive Window Auto-Tuning Level on TCP/IP

  1. Open a command prompt with administrator rights.
  2. Input the following command, and press Enter when done:

    netsh int tcp set global autotuninglevel=disable

  3. Restart the system.

If the problem still exists, it’s more likely caused by other reasons such as maximum concurrent connection attempt limit. In this case, we can re-enable the Auto Tuning for good.

Enable Receive Window Auto-Tuning Level on TCP/IP

  1. Open a command prompt with administrator rights.
  2. Input the following command, and press Enter when done:

    netsh int tcp set global autotuninglevel=normal

  3. Restart the system.