After reading Anand's iPad Air review, a few questions come to mind.
1) Does anybody have data on how much power each 4Gb LPDDR3 chip actually uses, ie is the difference between a 4 x 4Gb and 2 x 4Gb config more than 1W? I'm trying to ascertain if in certain conditions, i.e. browsing with many tabs open, that having to refresh tabs that have been kicked out of memory is actually more detrimental to overall power use than having a larger RAM pool in the first place.
2) Anand guesses that unlike the 5S, which stacks the RAM onto the SoC using PoP, the iPad Air, like its predecessor uses an external DRAM interface. If the A7 silicon is the same between phone & tablet, why change the memory packaging? Does PoP affect yields, or are there other drawbacks, that mean its use is only beneficial if packaging space is the primary restriction?
3) I don't believe that Anand updated the 5S to 7.0.3, so on the GPU tests the gap between phone & pad are artificially higher than they should be. I believe that any difference in performance is down to looser thermal restraints, rather than GPU clockspeed.