In Beta 10, whenever I clicked on a link to view a new page within a website, the page would not re-draw any elements it did not have to. This meant all background/container divs stayed in place and it almost felt like the website was completely ajaxed. It felt VERY snappy.
Now in beta 11, pages take much longer to load and actually end up re-drawing elements. It's almost as if the memory cache isn't working anymore.