Apple TV "single core" A5 actually has two cores, one is off

Posted:
in iPod + iTunes + AppleTV edited January 2014


An investigation into the custom A5 chip used in Apple TV has found that the new Application Processor uses both a smaller, more efficient 32nm die process and actually incorporates two cores, one of which is simply turned off.



According to a report by Chipworks, the custom A5 "APL2498" used in the third generation, 1080p Apple TV has improved upon the 45nm LP CMOS process of the previous A5 "APL0498," used in both iPad 2 and iPhone 4S last year.



The smaller die size makes the Apple TV's A5 almost 41 percent smaller than the original part, allowing more chips to be created from a single silicon wafer. That makes producing the part cheaper, and also helps improve performance and lower power consumption (as its components are shrunken down and therefore closer to each other).









In addition to being smaller, Chipworks found that the new version of the A5 actually incorporates two cores. Apple only advertises Apple TV as having a single core chip, so the investigation notes that "either Apple is only utilizing one core or they are binning parts."



By turning off one core, Apple could reduce the power consumption of a device. However, Apple TV lacks the power constraints of battery-powered mobile devices, making it more likely that the company simply developed a smaller, cheaper version of the A5 and is using the dual core rejects to power Apple TV, where one core is sufficient.



Chipworks explains that such "parts binning is a common process in semiconductors where devices are segregated (binned) based on meeting a subset of the overall requirements, in this case they could disable the 'bad' core, this increases the usable die per wafer, lowering the cost."



Chip makers routinely create CPUs and RAM components and test them for the highest speed they can consistently operate at, selling the fastest parts for more and the slower components for less, rated to work at a slower clock speed.



This strategy would allow Apple to use its poorest performing new A5 chips in the $99 Apple TV, while creating a new supply of fully functional 32nm A5 chips that are faster, smaller and cheaper than last year's 45nm batch.



Chipworks notes that these chips could either power a new generation of iPhones (or other devices) or help to reduce the cost of existing products such as the iPhone 4S or iPad 2. The latest third generation iPad uses a custom chip Apple calls A5X, which incorporates the same dual ARM cores but delivers quad-core GPUs to drive its Retina Display, with four times the pixels.



[ View article on AppleInsider ]

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Comments

  • Reply 1 of 52
    tylerk36tylerk36 Posts: 1,037member
    I wonder if Apple will start to release new chip models like they do the iPhone. For example. iPhone 3G, iPhone 3Gs. iPhone 4, iPhone 4Gs. A5, A5x. A6, A6x and so on.



    Just a thought.
  • Reply 2 of 52
    stelligentstelligent Posts: 2,680member
    Two cores. Only 1 in use. Very anthropomorphic.
  • Reply 3 of 52
    solipsismxsolipsismx Posts: 19,566member
    Odd title. The use of only one core was already known. What wasn't known is Apple using the new Apple TV and the new $399 iPad 2 (2,4) as the testbed for the 32nm process.
  • Reply 4 of 52
    macxpressmacxpress Posts: 5,001member
    I assume this could be for heat issues, or possibly power? I can't see any other reason why they'd disable the other core.
  • Reply 5 of 52
    isheldonisheldon Posts: 570member
    Quote:
    Originally Posted by stelligent View Post


    Two cores. Only 1 in use. Very anthropomorphic.



    Where is oneCoreWhore when we need him?
  • Reply 6 of 52
    drfreemandrfreeman Posts: 111member
    Quote:
    Originally Posted by macxpress View Post


    I assume this could be for heat issues, or possibly power? I can't see any other reason why they'd disable the other core.



    Whenever a chip is fabricated, tests are performed on them to ensure that hey all work correctly. There are times that parts of the chip may work and others won't (this defines the number of faulty chips and the yield of the fabrication process)



    What Apple is doing here is that if there is at least one functional core, they put it in the Apple TV instead of throwing the chip away.
  • Reply 7 of 52
    solipsismxsolipsismx Posts: 19,566member
    edit: Pipped by DrFreeman.
  • Reply 8 of 52
    stelligentstelligent Posts: 2,680member
    Quote:
    Originally Posted by iSheldon View Post


    Where is oneCoreWhore when we need him?



    You want more gore from oneCoreWhore?
  • Reply 9 of 52
    originalgoriginalg Posts: 383member
    edit: Pipped by DrFreeman as well
  • Reply 10 of 52
    shrikeshrike Posts: 494member
    Man, the prediction business is hard!



    Something is afoot.
  • Reply 11 of 52
    isheldonisheldon Posts: 570member
    Quote:
    Originally Posted by stelligent View Post


    You want more gore from oneCoreWhore?



    Ooops- I meant 8CoreWhore!
  • Reply 12 of 52
    tipootipoo Posts: 1,058member
    And there ya go. Some people got upset for some reason in articles where myself and some others suggested it was die-harvested. Its a normal practice, no reason for Apple not to do it.





    More interesting is that this is 32nm rather than 45 like the A5X, I wonder if that means a silently updated 2012 iPad with lower power consuming 32nm chips.
  • Reply 13 of 52
    solipsismxsolipsismx Posts: 19,566member
    Quote:
    Originally Posted by Shrike View Post


    Man, the prediction business is hard!



    Something is afoot.



    They are testing a new new process node with a low-volume product. I don't think we've seen Apple do that before, but it's also not surprising that they would as 32/28nm is expected to be in volume for the 6th gen iPhone.
  • Reply 14 of 52
    umrk_labumrk_lab Posts: 550member
    Quote:
    Originally Posted by DrFreeman View Post


    Whenever a chip is fabricated, tests are performed on them to ensure that hey all work correctly. There are times that parts of the chip may work and others won't (this defines the number of faulty chips and the yield of the fabrication process)



    What Apple is doing here is that if there is at least one functional core, they put it in the Apple TV instead of throwing the chip away.



    When is the class action regarding this faulty Core ?
  • Reply 15 of 52
    solipsismxsolipsismx Posts: 19,566member
    Quote:
    Originally Posted by umrk_lab View Post


    When is the class action regarding this faulty Core ?



    "DoJ files suit against Apple for colluding with chip manufacturers to disable cores in Apple TV and iPads."
  • Reply 16 of 52
    stelligentstelligent Posts: 2,680member
    Quote:
    Originally Posted by DrFreeman View Post


    Whenever a chip is fabricated, tests are performed on them to ensure that hey all work correctly. There are times that parts of the chip may work and others won't (this defines the number of faulty chips and the yield of the fabrication process)



    What Apple is doing here is that if there is at least one functional core, they put it in the Apple TV instead of throwing the chip away.



    This is an assumption on the parts of ChipWorks. It may well be correct, or not. One problem with this premise - it is based on another assumption: that Apple is producing millions of smaller versions of A5 (APL2498) and are picking off some of the defective ones to use in AppleTV. So Apple is already manufacturing this 32 nm A5 in sufficient volume that one specific defective species is sufficiently large in quantity as to supply another product line? Pretty big assumption.
  • Reply 17 of 52
    tipootipoo Posts: 1,058member
    Anyone else think they are trying to get 32nm production mature enough for 32nm parts in the next iPhone? The rumour was that it would have an power enhanced A5X, sounds like a 32nm one to me.
  • Reply 18 of 52
    brutus009brutus009 Posts: 356member
    The most obvious prediction here is that they're busy making 32nm SOCs for the next iPhone, which makes a lot of sense since it would otherwise be very difficult to fit 45nm improvements into the current form factor.



    What I'd like to know is:

    How many GPU cores are there?

    I'm looking at the above photos and I can't tell.



    NOTE: The Article incorrectly references a "33nm" die. Everything I've previously read has pointed to the development of either 28 or 32nm dies across the different manufacturers.
  • Reply 19 of 52
    tipootipoo Posts: 1,058member
    Quote:
    Originally Posted by brutus009 View Post


    What I'd like to know is:

    How many GPU cores are there?

    I'm looking at the above photos and I can't tell.





    As a reference:







    Looks like 2 to me, like the A5.
  • Reply 20 of 52
    solipsismxsolipsismx Posts: 19,566member
    Quote:
    Originally Posted by tipoo View Post


    Anyone else think they are trying to get 32nm production mature enough for 32nm parts in the next iPhone? The rumour was that it would have an power enhanced A5X, sounds like a 32nm one to me.



    I agree this all about getting the process issues ironed out. But it doesn't look like it will be Cortex-A9-based.
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