Internet Explorer slow on first open

Configuring new laptops we found that Internet Explorer was very slow loading the first time when connecting to a new network (in our case wireless networks).  This was with IE8, IE9, IE10 on a Windows 7 x64 machine using both the 64 and 32 bit versions of IE. 

After many hours of cursing I found that this was due to the following setting:
Internet Options, Connections, LAN settings, Automatically detect settings.

Unchecking this options fixed the issue.


In the registry this is found here:
reg add "HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections" /v "DefaultConnectionSettings" /t REG_SZ /d 460000001e00000001000000000000000000000000000000010000000000000018dc31de5756ce0100000000000000000000000000000000 /f

In particular, the 01 set that I have bolded is what disables it (09 is enabled).
http://social.technet.microsoft.com/Forums/en-US/winserverGP/thread/cb6abb30-4360-4d3d-93fc-61823b2a5c20

Note: in our case this only effected WLAN connections.  Broadband and LAN did not display the issue (unless WLAN was also connected at the same time).