Bad smoothing in ff (v_3.6.6)

Hi.

I made an animation using .animate() method and it's smoothing badly in FF of version that i've mentioned above. I tried this animation in ie 6 / ie 7, chrome, opera 10.53 (in opera 9.2 animation is also not the one in other browsers) and it's "flying". Here is an example.

Does anybody know smth about this issue?