This is interesting... Do you want to boost your browser?! Who doesn't!? :)
Take a look at http://weblogs.asp.net/rosherove/archive/2006/07/12/Make-IE-and-FireFox-go-faster-than-ever.aspx
Interesting but IE has two registry keys that set number of connection to server. Copied from http://www.regxplor.com/tweak11.html (the post is from October 17, 2001. How did I miss this?!)
"Go to the registry key:
Look for the following values:
If they don't exist, create them as DWORD values.
Set these values to the number of simultaneous connections you want to allow. A good value is 50." Download tweak11.reg!(.18 KB)