In an attempt to try to help diagnose and solve problems Windows 7 comes with troubleshooting wizards…Nothing fancy at first, right? Click on the Start button and type troubleshooting and up comes the troubleshooting menu:
So it can help me fix hardware and sound, fix the looks of things, improve power and a few other bits and bobs. However, what is really cool is looking under the hood at these troubleshooting tools.
Windows 7 and Vista include a "new & re-written" TCP stack that aims to take full advantage of hardware advances such as gigabit networking. Among the new features is Receive Window Auto-Tuning Level for TCP connections. TCP AutoTuning enables TCP window scaling by default and automatically tunes the TCP receive window size for each individual connection based on the bandwidth delay product (BDP) and the rate at which the application reads data from the connection, and no longer need to manually change TcpWindowSize registry key value which applies to all connection. Theoretically, with TCP auto-tuning, network connection throughput in should be improved for best performance and efficiency, without registry tweak or hack. However, this is not always the case, and may cause some Internet related issues and problems.
The workaround or solution to the above problem is to disable the TCP/IP AutoTuning. Disabling auto tuning of TCP Windows Size should not cause any negative effects, only that TCP Window Size will always at default value without ability to optimization to each connection. If there is any side effects after disabling auto tuning, simply re-enable it.
To check the state or current setting of TCP Auto-Tuning open an elevated command prompt and type:
netsh interface tcp show global
The system should display the following text on screen, where you can check the Auto-Tuning settings ( normal means it’s on – disabled means it’s … well disabled 
)
Querying active state…
TCP Global Parameters
———————————————-
Receive-Side Scaling State : enabled
Chimney Offload State : enabled
Receive Window Auto-Tuning Level : normal
Add-On Congestion Control Provider : none
ECN Capability : disabled
RFC 1323 Timestamps : disabled
To disable Auto-Tuning in the elevated command prompt type:
netsh interface tcp set global autotuning=disabled
If it all goes pear shaped and you need to re-enable Auto-Tuning the command is:
netsh interface tcp set global autotuning=normal
Give it a go and see if it helps your connectivity!
