Hi there, thank you for the post. I just wanted to add a few observations on behalf of the Internet Explorer team.

Firstly, no browser offers a perfect implementation of the Canvas 2D API specification to date - we've documented and shared a few examples from our test suites here: http://samples.msdn.microsoft.com/ietestcenter/#html5Canvas

As has been well noted, the IE9 build tested was our beta.

Secondly, in response to the specific issues raised, Giorgio Sardo has posted a response on his blog here:
      http://blogs.msdn.com/b/giorgio/archive/2011/01/14/building-great-browsers-together.aspx

We'll update this entry over time.

Thanks for listening,

Tim Sneath | Microsoft Corp.

Hi, we've posted an official response and explanation at the bottom of this post:
http://blogs.msdn.com/b/ie/archive/2010/11/17/html5-and-real-world-site-performance-seventh-ie9-platform-preview-available-for-developers.aspx

Bottom line - we built an optimizing compiler into the Chakra JavaScript engine that eliminates dead code where it finds it.

It's a fun conspiracy theory that we'd somehow 'game' SunSpider in this way, but it doesn't make sense that we'd go to all that risk to cheat on just one test out of 26.

Best wishes, Tim Sneath | Microsoft