Ryan Breen: A few weeks ago, I discussed IE8's improved connection parallelism, specifically the increase from 2 concurrent connections per host to 6. One open question was the total number of connections allowed — my speculation was that the IE team would stick with a max of 6 rather than triple that value as well.
I was wrong. The new max is an astonishing 18 (!) concurrent connections:
That is some serious parallelism, and it has significant implications for application performance.
In December of 2006, I discussed the CNAME trick for circumventing browser connection limits, using 3 hostnames to serve images to trick the browser into using all available connections. At the time, that was 6 for IE. The above capture from IBM Page Detailer confirms 18 concurrent connections in IE8.
Internet Explorer 8, IE8, Testing, Parallelism