I'm sure Microsoft is very proud of IE's hardware acceleration but their marketers are taking it a step too far when they lie about Firefox's hardware acceleration and mislead people about their own.
Microsoft is the kind of company that won't be fazed by the unwashed Web masses calling them out for bad behavior (the decade of IE 6, 7, and 8 have proved that) but that doesn't mean we shouldn't do it when appropriate and I think this is definitely one of those cases.
So what is Microsoft's big lie this time around? It's not hard to spot it in their recent blogging and other PR activities: that they alone have "full hardware acceleration".
This is just bullshit marketing speak. It means absolutely nothing. No browser has full hardware acceleration nor should they because not all parts of the browser benefit from running on the specialized graphics processor.
Firefox accelerates Web content on Windows 7 using the same set of Windows APIs IE 9 does and the performance characteristics of this acceleration are very similar on most balanced tests across the two browsers.
There are some tests where IE's acceleration has small advantages over Firefox's and some cases where Firefox has small advantages over IE's. In upcoming releases of both browsers, those small differences will mostly disappear.
But what really demonstrates the bogosity of their claim to exclusive "full hardware acceleration" is that IE doesn't even accelerate something as basic scrolling a Web page. Firefox 4 does -- and gets about a 10x win over IE 9 in a simple scrolling test.
I don't blame the IE engineers for this. They've done a fine job with IE 9. I predicted long before anyone else that IE 9 was going to be a great release with a lot to be really excited about (especially if you're a Web developer) so I'm really quite happy about the solid progress that team has made, but I'm really unhappy to see Microsoft's marketing yahoos spewing this kind of trash in the lead-up to their release. It doesn't serve users and it's a black eye on all the great engineering that went into IE 9.
Microsoft, I call on you to stop making this wrong claim now. You do not have "full hardware acceleration" and what you do have is less complete than Firefox's. Continuing to lie about both IE 9 and Firefox is a disservice to users and to your own engineering team.
You can get more technical details over at Robert's blog, here and here.