As we know already IE8 doesn’t pass the Acid 3 test, it scores 24/100, the new IE9 build managed to score 32/100 which is not good but it shows an improvement. Since this is a very early build things may improve in the future.
The most interesting feature they are working on in IE9 is the graphics acceleration, IE9 can use the graphics card for the rendering graphics and text using DirectX technology installed on windows systems.
Bringing the power of PC hardware and Windows to web developers in the browser. The PC platform and ecosystem around Windows deliver amazing hardware innovation. The browser should be a place where the benefits of that hardware innovation shine through for web developers.
re changing IE to use the DirectX family of Windows APIs to enable many advances for web developers. The starting point is moving all graphics and text rendering from the CPU to the graphics card using Direct2D and DirectWrite. Graphics hardware acceleration means that rich, graphically intensive sites can render faster while using less CPU.
The support for some HTML5 elements in IE9 is still in the discussion stages, HTML5 is still in draft stage. Nevertheless it will support HTML5 elements and CSS3 selectors.
Channel 9 has posted some videos related to IE9, i have embedded them below. These videos are silverlight based, you need silverlight installed to view them.