This test is mainly for Chrome and webkit based-browsers which utilize -webkit-transform-style: preserve-3d; to enable hardware acceleration. You can see the difference by the slight blurring that occurs when enabled. To check FPS, you can use about:flags and enable the FPS counter (which only appears when hardware acceleration is in use.)
The animation will work in Firefox 4, but with box shadow on, the performance isn't great (CPU utilization ~25% in our limited testing).
More information about this demo: see blog post.Spin! Toggle preserve-3d OFF Toggle box shadow OFF