This is weird, and it seems to be only happening to me as I can't find anything on the 'net about it. Retina MBP 15", OS X 10.8.5. When scrolling the MacRumors site the page flashes/flickers (it gives the appearance of constantly blanking the page and redrawing it in sections). It only happens with the MacRumors site (these forums are OK). The problem only started around the time of the 10.8.5 upgrade. I've not made any changes to Safari recently, e.g. added or removed extensions. I've tried clearing the cache (Develop menu). Any ideas?