Does anyone know why apple went this way? Seems like the A8x was a hack to make it faste while A9 is the on they always wanted. Kinda like the S phones always had the significantly better A chip
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Air 2 has three cores 9.7 Pro has two?
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The A8x has a three core could that offers each core at a slower clock speed each. I believe each core is clocked around 1.6 GHZ I believe but I could be wrong since I haven't researched it in a while. The A9x has two cores clocked at or around 2.0ghz I believe. Apple must of found the dual core with higher clock speeds ran better then the three core and if I am not mistaken a dual core would be better with battery life?
Take it with a grain of salt considering its the Wikipedia article for them but here are the two cpus.
The A8x is a triple core clocked at 1.5 ghz on the 20nm chip and the A9x is a dual core clocked around 2.16 ghz on a 16nm chip. 16nm means the chip dye is smaller which i know every chop maker wants smaller which might mean more power efficient chips?
A plausible theory from AnandTech.
http://www.anandtech.com/show/9766/the-apple-ipad-pro-review/2
http://www.anandtech.com/show/9766/the-apple-ipad-pro-review/2
AnandTech said:
I will take the A9X with 2 cores running 2.26 Ghz.
I wonder what the difference in power consumption is between the two.
I wonder what the difference in power consumption is between the two.
Yeah and the iPad Air 2 isn't far behind the iPad Pro 9.7" in multi-core benchmarks. The biggest difference is in single-core performance, so apps that are single threaded like Safari will see a more noticeable benefit. IDK if iMovie is multithreaded, but if it is (and it should be) then the iPad Pro won't render out videos much faster than the Air 2. For most people the difference between the two when it comes to performance is negligible. High-end games will probably play smoother.
My theory is that the A8X was supposed to be exclusive to the iPad Pro if it would have been released as originally planned in March 2015, hence why it's also missing the many new features from the 9.7" Pro. If that would have happened, the Air 2 would have had an A8 and the mini 4 would have been the mini 3 (it's suspicious enough that its only upgrade was Touch-ID). When Apple realized they couldn't meet their schedule for the iPad Pro's release date, they pushed it back and developed the A9X specifically for it. There's an article about this somewhere.
This is Very Plausible. Because the A8X CPU is only in the iPad Air 2 No other device shares it or its GPU. Fast sure but Not a Target for any developer due to its Limited install base.
Developers will Target the A9 and 2GB RAM from here on out for AA Apps.
Meanwhile the A9X will blaze through those Apps and see dedicated Pro Software
The A8X will be left to just sit there. A8X compared to an 2 Core A9 its amazing how close they are.
Also your theory has more weight to it given how separated and different features the 9.7 and 12.9 have the 12.9 was supposed to have True Tone but technical issues and schedule forced the delay.
In the end Apple said we need an iPad Air 1 replacement and all they could come up with was the A8X. A souped up A8 with 1 More Core.
So whats gonna happen to A8X devices ? as developers Target A9 and 2GB DDR4 RAM the iPad Air 2 the only device with an 3 Core A8X and 2GB DDR3 RAM will start to lag or stutter ahead of its time.
the A8X represents the end a an era with Apple you don;t want the fastest last gen tech you want the Newest Gen Tech an thats A9 level and A9 level GPU. A9X even better.
The majority of user-responsive real time processing is still not written for parallel processing. This means that single core remains the most important metric of performance for most situations.
Any kind of serious CPU crunching like rendering will benefit from multi core performance, but that's not how most people are using these devices. Some game engines make good use of multicore CPUs but.. Who cares? (Don't answer that)
A8X used a third core because the single core speeds of that generation barely moved from A7 while power efficiency increased, leaving the iPad with enough thermal headroom to add a third core and see multicore gains.
A9 saw another leap in single core, and a dual core A9X now uses all of the thermal clearance the iPad's passive cooling can provide. Adding a third core under these conditions would have very little impact on performance.
Any kind of serious CPU crunching like rendering will benefit from multi core performance, but that's not how most people are using these devices. Some game engines make good use of multicore CPUs but.. Who cares? (Don't answer that)
A8X used a third core because the single core speeds of that generation barely moved from A7 while power efficiency increased, leaving the iPad with enough thermal headroom to add a third core and see multicore gains.
A9 saw another leap in single core, and a dual core A9X now uses all of the thermal clearance the iPad's passive cooling can provide. Adding a third core under these conditions would have very little impact on performance.
Likewise on the desktop on most operating systems. That's why my quad core Skylake PC is about 20-30% faster than my 12 core Mac Pro in many real world productivity tests.
I was thinking the same, love these threads where people discuss about Apple hardware decisions.
I myself always wondered why the A8X is the only Apple mobile chip that has three cores.
My theories were that either :
-The A8 did not have enough big jump in both CPU and GPU performance compared to A7 so they could not put that chip into the beast that they wanted the iPad Air 2 to be. They either had to make an A9 chip which would make the new iPhone 6/6 Plus a bit obsolete already and also cost more to make or create a chip based on the A8 and just add a third core to increase performance.
-At that time (end of 2014) they did not have the ressources or manufacturer to make a really powerful chip like the A8X with only two cores so they had to put a third core to have this performance. That would also explain the very small performance gain from the A8 over A7.
Pretty amazing that apple could just add a third core like that and not even be a chip company. Yeah i know that is 1990s thinking