Comment 1 for bug 45357

Thanks for your bug report.

www.silicon.de is an extremely complicated page. The main HTML of the page is also huge (weighing in at 258,485 bytes) and it triggers quirksmode to boot. During rendering for me firefox uses as much of the CPU as it can get for about 10 seconds. After this period things return to normal. This is under GNOME.

Given that site's size, disregard of standards and complicated layout I'm not surprised the browser became unresponsive. I suspect any request for increased threading to maintain UI resposiveness during page rendering would have to be an upstream feature request though.