This won't have near the performance of the Haswell-U series, so it's unlikely that it would be used in a Macbook Air variety.
Not exactly. The quote in the article: "but existing MacBook Air computers utilize the Haswell-U series chips that run at 15 watts while the Core M operates at approximately 5 watts, making it unclear whether it would be possible for a Retina MacBook to be powered by the Core M chip." is very misleading.
Broadwell does not utilize some sort of magic to reduce power by 3x. Instead it's been tooled to provide *substantial* dynamic range. You CAN run it at 5W --- in which case it will perform, I expect, about the same as an Apple A7. You can also run it at 15W, in which case it will perform the same as (actually about 5% better than) an existing Haswell at that power. [The IPC is about 5% better. To be fair, the transistors are lower power and there's been another round of optimization, so at the same power you may also get say 2.6 or 2.7GHz rather than the 2.4GHz or so you'd expect for a Haswell in this role, so all round maybe 15% better at the same power.]
The dynamic range is not to be sneered at. This is REALLY hard, and is one of the two places Apple seriously lags Intel. (The other is using a Network on Chip for communication, rather than a bus; but my guess is that this is already fixed as the central feature of the A8.) But the dynamic range, as I said, is not magic. It allows you to dial the CPU down low for when you don't want to exceed a temperature limit, or somehow know that the work you need to do is not high priority and can run slowly. It also allows you to run at max speed for short bursts to make the device feel really snappy. Basically it's the next rev of the turbo-ing of all Intel CPUs of the last ten years.
Point is
- this is a great chip for a laptop. Delivers snappiness, but also lower power than Haswell for all those times the CPU doesn't have THAT much to do.
- this is a great chip for the Surface Pro 4, for the same reasons.
- this is not a magic chip for RT tablets, or Android, or phones. It will make those devices snappy (which is definitely valuable) but it will NOT give them simultaneously on-going Haswell performance and phone/tablet lifetimes with normal phone/tablet batteries.
- it will, I'm sure, cost so much that the ONLY vendor in this space who'll use it for sub-laptop is MS.