Video is still a moving target, due to Virtual Video Cards (DisplayLink, Hypervisors, etc.) Also some Win32 code can impact Video Drivers/Performance....
I can see that's true, but it seemed people were talking about the primary display of the SP2. I thought more or less the Windows part wouldn't be that different, to the extent "official" updates have been used. Maybe that's not the case (owners installing 3rd party drivers, et. al.), but if it is ("official" updates only), the widely variant results remain a mystery.