Browser Max Parallel Resource Requests 2013

The HTTP/1.1 spec, which suggests that browsers download two components in parallel per hostname, is currently rarely followed by browser vendors. 

BROWSER	MAX PARALLEL CONNECTIONS PER BROWSER Numbers resources [.js, images, .css]  that can be downloaded using a browser
IE 6, 7	2
IE 8, 9	6 Registry Tweak to 16  - http://www.enhanceie.com/ie/tweaks.asp
IE 9	6 ditto
IE 10	8 ditto
Google Chrome 1,2	6 hard coded
Google Chrome 3	4 hard coded
Google Chrome 4 -> 23	6 hard coded - Request ability to modify here.... https://code.google.com/p/chromium/issues/detail?id=12066
FireFox 2	2
FireFox 3	6
FireFox 4 -> 17	6 Change use URL about:config -> network.http.max-persistent-connections-per-server - can be changed to 1 and 255 inclusive avg. 16
Firefox  17 ->19	6 Change use URL about:config -> network.http.max-persistent-connections-per-server - can be changed to 1 and 255 inclusive avg. 16
Opera 10	8
Opera  11,12	6
Safari 3,4	4 hard coded

YUI (http://yuilibrary.com/) recommendation is to increase the number of parallel downloads by using at least two, but no more than four host names. Once again, this underscores the number one rule for improving response times: reduce the number of components in the page. 

Read full article here.....
http://www.yuiblog.com/blog/2007/04/11/performance-research-part-4/