Cisco AnyConnect Secure Mobility Client VPN slow using AT&T U-verse

Problem:

I was recently struggling with a slow or unusable VPN connection when using Windows 8.1, Cisco AnyConnect Secure Mobility Client VPN version 3.1.04066, and a Wireless connection to a 2Wire Gateway 3600HGV. 

Without VPN, my speedtest.net results are:

With VPN, my speedtest.net results are:

Solution: 

The solution that I found so far was to edit a field in a file called preferences.xml.  This file is found under

/<Username>/AppData/Local/Cisco/Cisco AnyConnect Secure Mobility Client

Originally, there was a line that showed this…

<SDITokenType></SDITokenType>

and my performance results were…

I edited the file using Notepad to look like this instead…

<SDITokenType>none</SDITokenType>

Now, my performance results are…

Then I removed

<AutoConnectOnStart>false</AutoConnectOnStart>
<BlockUntrustedServers>true</BlockUntrustedServers>
<LocalLanAccess>true</LocalLanAccess>

Now, my perfomrnace results are…

When VPN doesn’t work, its frustrating to figure out what has gone wrong.  This solution worked for me so far.  I hope it works for you.