Trying to figure out which Intel graphics chip the new 13" MacBook Pro Retina uses. Apple just says it's an Intel Iris GPU. I think that means it's a 5100 (the Iris Pro in the 15" is a 5200). If it is a 5100 then it's only a tiny slither slower than than the 5200, which would be awesome for the 13" laptop. Can anyone confirm this?