I imagine you are aware the dual core iPad Pro CPU outperforms the triple core iPad Air 2 even in multicore tests. Each of the iPad Pro cores are much more powerful than the iPad Air 2 cores. And much of the developed code uses basically only one core. A quad core CPU in A10 (if real) would surely have a reduced power per core, due to iPad thermal constraints, or at least not a too increased single core performance.
You should be aware in Android world there are octacore processors which are much less powerful the iPhone dual core CPUs. So number of cores as a performance metric is useless.
Of course a CPU improvement will be attained, but you should not expect iPad Air 2 be faster than iPad Pro, and any iOS product can expect no less than 3 years of support.
+1
Apple is perfectly able to NOT to fall for the "I have more cores then you" war. There are many times when the stubbornness of Apple is annoying, this but this one of those occasions where they have a really good point. It's silly to have an octacore processor in a phone, not any phone can have all cores running at full capacity because of thermal constraints. The individual cores are usually slow and there is no software that can use 8 cores effectively, so it's pretty useless.
The A8X was a triple core because they couldn't gain enough processor speed vs thermal dissipation vs efficiency vs thermal constraints. But the A9X went back to 2 cores and I expect the A10X to be 2 cores again. Most people don't realize that Apple is really good at designing those ARM processors, but if you would want some good insight into it, Anandtech.com has some really nice articles on the subject:
http://www.anandtech.com/show/9766/the-apple-ipad-pro-review/2
Really worth while reading:
From Anandtech:
The fact that Apple dropped back down to 2 CPU cores is unexpected given that we don’t expect Apple to ever go backwards in such a fashion, and while we’ll never know the official reason for everything Apple does, in retrospect I’m starting to think that A8X was an anomaly and Apple didn’t really want a tri-core CPU in the first place. A8X came at a time where Apple was bound by TSMC’s 20nm process and couldn’t drive up their clockspeeds without vastly increasing power consumption, so a third core was a far more power effective option.
Overall this means that iPad Pro and A9X will set a very high bar for tablet CPU performance. As we’ve already seen in the iPhone 6s review, the Twister CPU core is very potent and in most cases faster than any other ARM CPU core by leaps and bounds. Cranking up the clockspeed a further 22% only serves to open up that gap even further, as Twister is now reaching clockspeeds similar to the likes of Cortex-A57 and A72, but with its much wider execution pipeline and greater IPC. This is also the reason that an Intel Core CPU comparison is so interesting, as Intel’s tablet-class Core processors in many ways are the target to beat on overall CPU performance, and we’ll be touching upon this subject in greater detail a bit later.
