IE9 Final Preview Released

Microsoft is preparing for their first beta release of Internet Explorer 9 in September now that they've released the fourth and final developer preview version today.  This release integrates Microsoft's Chakra JavaScript engine to run natively inside the browser.  It also finishes the hardware acceleration features and boosts the Acid3 scores. 

Dean Hachamovitch, the general manager of IE, says that this fourth preview release has fixes for some previously reported bugs and contains the finished GPU acceleration features for text, audio, and video.  The development team also met their goal to integrate "the JavaScript engine natively inside the browser, rather than bolting it onto the side to support multiple JavaScript engines as some other browsers do today," said Hachamovitch.  This was a reference to Firefox and their TraceMonkey and JaegerMonkey JS engines.  While Hachamovitch dismissed the JS engine competition as a "drag race" during IE8 development, he and his developers are drawing more attention to their development of Chakra. 



Microsoft's SunSpider benchmark of this preview release puts it ahead of every browser except Chrome 5+ and Opera 10.6.



Microsoft's Acid3 benchmark of IE9 preview 4 also had marked improvement.  It improved 14% since preview 3 with a score of 95/100.  The final 5 % of the web standards score consists of "in transition" specs, according to Microsoft, so it's unlikely that they'll get full support until there is consensus.



So far, Microsoft has contributed 519 new tests to web standards bodies with preview 4.  They've contributed a total of 2,138 during the whole of IE9 development so far.  Here's a look at how compatible Microsoft's submitted tests are across several browsers.



The fourth IE9 developer preview can be downloaded here.  At the Web 2.0 Expo in May, Microsoft said that IE9 would not run on Windows XP.  Hope you're ready to upgrade.