It has taken some time for Microsoft to concede that IE9 isn't the only browser with hardware-acceleration support. The IE team ignored Firefox until Firefox 4 Beta 5, when Firefox turned hardware acceleration on by default (even if the feature has been available through manual activation since Firefox 3.7 b5-pre).
So how does Microsoft react? It stomps its feet and says that IE9 has the better and more complete hardware-acceleration integration: "Keep in mind that not all hardware acceleration is equal," wrote Microsoft's Ted Johnson. "Today, IE9 is the first and only browser to deliver full hardware acceleration of all HTML5 content." Mozilla's Mike Shaver shot back in a Twitter post: "MSFT is wrong; we accelerate content and compositing, and we will do partial on XP as well (unlike IE9)."
Shaver's note is based on the fact that IE9 is available only for Windows Vista and 7. Firefox will not be able to render content through hardware acceleration, but the browser will support hardware acceleration in layer compositing through Direct 3D. In Vista and Windows 7, content is accelerated with Direct 2D.
Microsoft's position is that hardware acceleration does not only consist of content rendering and "page composition" but also includes desktop composition. Just like Firefox, IE9 uses Direct 2D for content rendering and Direct 3D for layer (or page) compositing. The company claims that IE9 is the only browser that supports desktop compositing through the Desktop Window Manager (DWM): "Because IE9 uses DirectX and only DirectX, there is better interaction between IE9 and the DWM, using less GPU memory and resulting in better stability than browsers that mix different subsystems," Johnson wrote.
We have inquiries for more details in to Microsoft and Mozilla. We have not received answers yet but will offer updates as soon as we have replies.
For now, I can only judge the hardware acceleration implementations by their performance. Based on Microsoft's tests, there isn't much difference between IE9 and Firefox 4. Firefox 4 even beats IE9 in some tests. Can I be arrogant and say that I don't really care about another acceleration stage if it does not yield a tangible benefit?
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