Just curious - how necessary is the csshover.htc file?

With it, it seems that the :hover effect is slowed down by up to 1-2 seconds, but when I remove the reference (from the .css file, that is), things speed up and the :hover effects are instant. I've tested with and without in IE7, FF3, Opera 9, and it seems to be working fine in all 3.

Maybe it's just me having the problem (I'm testing this on a home server).

From what I've read, .htc files are only used by IE browsers, so I assume it is there to help older browsers? But I don't know.

One thing I do know - it would be nice to be rid of the sluggishness.