On upgrading a client's site to ZC157, admin home page very slow to load - about 9 seconds. So we uploaded a vanilla 157 and got the same results. Page initially loads OK but there is a long pause at the point of loading the new orders widget. Investigation suggested that it was related to looking up attribute data on each product.

With lines 48 - 56 commented out in RecentOrdersDashboardWidget.php , admin page load has reduced to a much more acceptable 1.34 seconds.