Try to use .fadeTo()
instead of .fadeIn()
and .fadeOut()
,
$('.box').hover(function(){
$('p.more',this).stop(true).animate({top:'30px',opacity:'1'},'slow');
$('img.icon',this).stop(true).fadeTo(300,0);
},function() {
$('p.more',this).stop(true).animate({top:'80px',opacity:'0'},'slow');
$('img.icon',this).stop(true).fadeTo(300,1);
});