Note: Please note that you can cause damage to your system if you make a wrong move when editing the Windows Registry, so you do so at your own risk. Back up your registry before attempting to use any of the registry tweaks.

The DefaultRcvWindow, sometimes known as TCP Receive Window or RWIN, is a buffer that fills with data determining how much of that data the receiving computer will receive. If the size of a DefaultRcvWindow is set incorrectly, then the speed of that Internet connection is affected. The DefaultRcvWindow can be specified within the Microsoft Windows Registry to maximise the performance of an Internet connection. Below are instructions on how to do this, again please always backup your registry before making changes to it.

Step 1: Open up the Windows Registry Editor. To do this click on the Windows Start button, click on "Run" and type in "regedit" before clicking "OK".

Step 2: Find the following registry key:

HKEY_LOCAL_MACHINE\ System\CurrentControlSet\Services\VxD\MSTCP

Step 3: Look for a string named "DefaultRcvWindow". If you don't have this then you will have to create it (see screenshot):

Step 4: Once you have located or created "DefaultRcvWindow", set the value of this to "256960" (without quotes).

Step 5: Close the registry editor and reboot your computer.