It turns out that Internet Explorer 9, in its 64-bit version, apparently has a different, slower JavaScript engine than its 32-bit counterpart. We didn’t know that when starting our browser tests, but we’ve now updated our tests with IE 9 32-bit results, at least in the JavaScript and CSS categories. Doing so gave IE 9 32-bit an edge in at least one category. Thanks to the eagle-eyed commenters and Twitter correspondents who pointed this out. More »