Real world JavaScript solution

This is the final look of the code to solve the nasty performance problems with the instant search.

if(!$.browser.msie) { /* SORRY, BUT IE IS *SLOW* WITH JQUERY */
    uls = $("#metrics ul:visible"); /* Nasty hack: */
    uls.hide();                     /* 500x speedup on Chrome */
    if(text == "") {
        $(field_search).parents(".search_realm").find(".search_item").show();
    } else {
        $(field_search).parents(".search_realm").find(".search_item[id*="+text+"]").show();
        $(field_search).parents(".search_realm").find(".search_item:not([id*="+text+"])").hide();
    }
    uls.show();
} else { /* IE SPECIFIC ALGORITHM (x10 speedup on IE) */
    $( field_search ).parents(".search_realm").find(".search_item").each(function(){
        if(this.id.indexOf(text) == -1){
            $(this).hide();
        } else {
            $(this).show();
        }
    });
}

So, what happened here?
1. The horrible, horrible Chrome performance was due to a too-early rendering attempt. Hiding the containing ul makes Chrome stop trying to render after each element "reappears" and causes no flicker on the screen. The time goes from 12000ms to ~70ms for a 1549 element set.
2. IE didn't like jQuery. Well, don't make it use jQuery. Simple, huh? ;)
Now Chrome is an absolute performance champion with times 30/70, where as IE stays in the 320's and firefox in the 300/150's.