[ryanpetrich]

Only when using transforms and only when using 3D transforms (though iOS5.0 may support hardware accelerated 2D transforms as well)

[rjett0]

You can hardware accelerate 2D transforms on iOS. You just do a -webkit-transform: translateZ(0); and it puts the element in the compositing layer.

[ryanpetrich]

Yes, that is a 3D transform.