What do you think the third core in the A8X is used for?

Andres Cantu

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Original poster
May 31, 2015
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Rio Grande Valley in South Texas
Now that we know that the iPad mini 4 has an A8 chip with 2GB of RAM, it is safe to say that the extra gig of RAM is the necessary component for split-screen multitasking. In that case, what do you guys think the third core in the A8X used for?

My theory is that they needed that third core because they knew that they would not introduce an iPad Air 3 this year, so they needed a chip that would still be considered fast a year after its introduction. Next year they'll probably put the A9X in the iPad Air 3, the A9 in the iPad mini 5, an A10X in the iPad Pro 2, and an A10 in the iPhones 7 and 7 Plus.
 

jev425

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Sep 12, 2014
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Seattle, WA
I think the air 2 even though it won't have the 3D Touch or whatever new "features" the newer iPads bring, will still be able to perform smoothly even two years from right now
 
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kevink2

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Nov 2, 2008
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The third core is just available for periods when extra threads need to work. Pretty much any phone/tablet, running off of battery, can't be running all cores full out very long or the battery will quickly go dead. And the device get hot. But, for brief periods, multithreaded apps can get stuff done faster with 3 cores than with 2 or 1.
 

Smoovejayy

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Jan 20, 2012
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A chip that could still be considered fast, a year after... its introduction.
This. My iPad Air 2 runs flawlessly, albeit I have to start from scratch since recovering data in the process of downgrading from 9.1 to 9.0 is a b***h. I love my iPad Air 2 but I honestly would like to know if it does take advantage of the third core. I think one user said it: when multitasking, the OS takes up the third core. Also for future proofing I suppose. I'm starting to see the separation between my 6S and Air 2: 3D Touch.
 
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rkuo

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Sep 25, 2010
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This. My iPad Air 2 runs flawlessly, albeit I have to start from scratch since recovering data in the process of downgrading from 9.1 to 9.0 is a b***h. I love my iPad Air 2 but I honestly would like to know if it does take advantage of the third core. I think one user said it: when multitasking, the OS takes up the third core. Also for future proofing I suppose. I'm starting to see the separation between my 6S and Air 2: 3D Touch.
Multitasking, definitely. You can also bet the extra core is helping with image decoding and other web page rendering tasks. Really depends on the apps.
 

Krevnik

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Sep 8, 2003
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Two split view apps take 2 cores and iOS takes 3rd core.
It isn't split like that. An app doing nothing (even if visble) should be fully idle and not be using any cores at all. An app that is multithreaded can be using multiple cores. Cores are not assigned to anything, but they are used to balance load on the CPU when possible.

More cores will benefit some scenarios where it can be multithreaded, by allowing work to be done faster and letting the CPU get back to sleep faster. There's also certain views in UIKit that intentionally split their drawing across multiple threads (anything using CATileLayer), those get better drawing performance with more cores so you don't get that "tile pop" during scrolling as badly.
 
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