During the MIX 11 keynote this morning, Joe Belfiore showed off the “Mango” update’s HTML5 rendering speed and Internet Explorer 9. He used a standard test from the IE Test Drive site to show how quickly the new IE9 on Windows Phone will render HTML5 when compared to a current iPhone 4 and Nexus S. In the Speed Reading test, the iPhone rendered about 2 frames per second, while the Nexus S Android phone handled about 11 frames per second, and the Windows Phone rendered about 26 frames per second. This is thanks to IE9’s GPU hardware accelleration features; the same rendering code found in the extremely fast desktop version of IE9.
UPDATE: Video added below.
Try running the same test for yourself here.