So I have a 13" rMBP that works great, but am seeing a ton of threads on here about the Retina MBP's struggling to handle so many pixels, etc. My question is why is this not the same issue with a retina iPad? I mean, the iPad has a pixel doubled 2048x1536 display and does not have an Ivy Bridge chip clocked at 2.5GHz or higher. Nor does it have 8GB of RAM. Can someone explain why the iPad has no lag issues and the seemingly much more powerful rMBP's may struggle?