A summary so far:
In the three rendering tests
http://html5test.com/
http://peacekeeper.futuremark.com/run.action
http://www.color.org/version4html.xalter
four Blink-based browsers perform best (see the OP and preceding post).
Gecko-based browsers (Firefox, K-Meleon, Pale Moon, etc.) score significantly lower (400's on HTML5 test).
For the color test, ICC4 support has to be manually turned on:
https://www.metalvortex.com/blog/2012/07/12/979.html
Trident-based browsers (Internet Explorer, GreenBrowser) rank dead last (302 on the HTML5 test).
Still waiting for someone to test Edge (Win10) and Safari...
- sutekh