why is this flying text rendering choppy?
===

I have this flying text marquis that is rendering really choppy as it flies in (especially in firefox) It seems to jump at certain intervals and i was wondering if i could make it run more smoothly by using easeIn or something similar. Any ideas on this?

I set up a jsfiddle here for convenience : http://jsfiddle.net/c6EHj/3/ 

html

                    <div id="taglines">
                        <h4>Your expert. Your partner.</h4>
                    </div>
                <div class="container">
                    <h3 id="fly1" class="flying-text active-text">Creative Solutions</h3>
                    <h3 id="fly2" class="flying-text">Graphics</h3>
                    <h3 id="fly3" class="flying-text">Sourcing</h3>
                    <h3 id="fly4" class="flying-text">Distribution</h3>
                    <h3 id="fly5" class="flying-text">Online Tools</h3>
                    <h3 id="fly6" class="flying-text">Custom Branding</h3>
                    <h3 id="fly7" class="flying-text">Personalized Support</h3>
                </div>​

css

     .container{
       width:1000px;
       margin:0 0 0 -10px;
       color:#c3cd25;
     }
     #taglines{
       color:#000;
     }
     #taglines h4{
       font-size:20px;
     }
     .flying-text{
       margin-left:-100px;
       font-size:40px;
     }


JS


        $(document).ready(function(){

	$('.container .flying-text').css({opacity:0});
	$('.container .active-text').animate({opacity:1, marginLeft: "350px"}, 4000);

	var int = setInterval(changeText, 5000);	


        function changeText(){
	
	var $activeText = $(".container .active-text");	
	
	var $nextText = $activeText.next(); 
	if($activeText.next().length == 0) $nextText = $('.container .flying-text:first');
	
	$activeText.animate({opacity:0}, 1000);
	$activeText.animate({marginLeft: "-100px"});
		
	$nextText.css({opacity: 0}).addClass('active-text').animate({opacity:1, marginLeft: "350px"}, 4000, function(){
		
		$activeText.removeClass('active-text');											  
	});
     }
     });