Remember the days when your WoW ping was sub-40ms? The good times are back, provided you are able to follow simple (or not so simple) instructions.
First of all, you will need to open REGEDIT, to do this, please go to Vista start menu and click on "RUN", a new window will open; enter "REGEDIT" and press ENTER.
Now that you are editing your system registry, doubleclick on "COMPUTER" and navigate manually to HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesTcpipParametersInterfaces and once there, find the entry that lists your current network IP address (if you dont know your IP address, chances are you shouldnt be attempting this fix). Under Interfaces you can find all of your network interfaces, no matter whether they are virtual, real, connected or disconnected, this is why it is paramount to find the one that corresponds to your network connection through which you play WoW.
Once you find the one entry that lists your network IP address right click on its code (left pane) and select "NEW" DWORD (32bit VALUE) to add a new parameter.
1st new parameter to add will be named "TcpAckFrequency" -- after you have added it, change its HEX value from "0" to "1" by double left clicking on it and editing the hex value. Do the same once again with "TCPNoDelay" parameter (add a new 32bit DWORD, name it TCPNoDelay), change its HEX value from "0" to "1". PRESS F5 (to save the changes you just made to your registry)
Open control panel scroll down to "Programs and Features", open it, look at the left pane and click on "Turn Windows Features on or off".
Wait a while for the list of windows components to be created. Scroll to MSMQ server options and add a checkmark to all its components. Press "OK" and REBOOT.
Once your computer reboots, go back into REGEDIT and manually navigate down to HKEY_LOCAL_MACHINESOFTWAREMicrosoftMSMQParameters and at this position add a new 32bit DWORD (same as before) called "TCPNoDelay" and change its HEX value from "0" to "1".
PRESS F5 (to save the changes you just made to your registry).