First off, how does the Receive Windows Auto-Tuning work? This feature basically lets Windows monitor the routing conditions in your network. Conditions can be things such as application delay, network delay or actual bandwidth. This allows connections to be configured by Windows thus scaling the TCP receive window to take advantage of your network performance.
This seems like it could be a great feature. Here’s the catch. If the Receive Windows Auto-Tuning feature is enabled for your HTTP traffic, some older firewalls, routers or even older operating systems may cause a slow data transfer — even if the devices are beyond your organizations, WAN, LAN or network. Microsoft notes that this issue (latency) will remain.
So how can you disable this feature? Open a command prompt as an administrator. Type the following in the open window:
netsh interface tcp set global autotuninglevel=disabled
Reboot your computer
Link – Although this says Vista, disabling Autotuning may improve performance – even on Windows 7