Intel HD 4000: MBA vs rMBP 13

Because the Intel HD 4000 needs to run 3 million more pixels on the rMBP than the MBA.

Yeah, but it is not needed.

If I remember correctly, the more RAM you have, the amount of video memory increases.

Does it matter? It might decrease performance in GPU intensive activities, like video editing. But an Air was never meant for that because of its 1.8 GHz ULV processor. The Pro is much more capable as it has a 2.5 GHz full voltage processor which may not perform much higher in GeekBench, but makes it a much better computer all-around, especially with its screen, I/O, processor, etc.

13" pro maxes out at 512mb as well. its probably overclocked in the retina to power the screen or somethin

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and oddly, my 11" with hd4000 and only 4gb ram is at 512mb. when my pro had the same hd4000 and 4gb ram it was 368mb or something. odd