[jQuery] Slow performance in IE7

[Sand Dragon]

I'm trying to use the hover event on a series of data with 18 columns
of data.  Here's a sample of the code:

$("tr.orders").hover(
        function() {    $(this).addClass("highlighted");        },
        function() {    $(this).removeClass("highlighted");     }
);

This works beautifully in Firefox and IE (specifcally v7) but in IE
the performance is exponentially slower.  Some of the pages I'm trying
to use this on display 45 to 50 rows and IE performs sluggish.  On a
full display page we include over 200 rows and that makes scrolling
with the mousewheel over the list all but unbearable and the
application of the style is sluggish once scrolling stops.  Any ideas
how I could increase the performance in IE7 for this type of
application.

James