How to make the menu running smooth?

Hello,

It seems my menu running not smooth (fast enough) when you drag mouse from one item to another items. It still has the delay between it. As i check a lot of other website, the menu running very smooth and fast.

You can take a look my website here and the example site here . Please try to move your cursor fast from one to one to see the different. Is there anyway to make my menu running like that?

Thank you,
Tuan.