Not smooth animation in Internet Explorer

Why in the Internet Explorer Actuate-animation aren’t smooth? I added FPS-counter and it shows about 60 FPS, but in Chrome, Firefox and Opera it shows about 120 FPS.

Also, if I use spritesheet-animations, in the Internet Explorer I see many freezes and lags, but in other browsers all is good.

Because of what it can be?

It might be related to WebGL or requestAnimationFrame support