Microsoft tried to downplay the launch of Safari 5 by posting its own comparison video (below, Silverlight needed) showing Internet Explorer 9's performance with graphics hardware acceleration. Apple is touting use of the GPU for the Windows version of its browser, but IE9 even in its test phase is shown drawing demo sites noticeably faster than Safari. Microsoft didn't say how many of the tests, which exist on the IE9 preview site, were hardware-enabled for both.
Internet Explorer's upcoming release is being designed from the ground up for hardware acceleration using DirectX in Windows to offload rendering certain kinds of code, such as HTML5. Apple is adding GPU rendering to the Windows version after the fact but has the advantage of a finished release where IE9 is still early in development and is unlikely to be ready in a finished form this year.