Inside iPad’s brain: the secrets of Apple’s ‘A4’ SoC

The reason that Apple is so secretive about their new “A4” processor that powers iPad, despite habit, it that the “A4 just isn’t anything to write home about,” Jon Stokes reports for Ars Technica.

“The A4 is a 1GHz custom SoC with a single Cortex A8 core and a PowerVR SGX GPU,” Stokes reports. “The fact that A4 uses a single A8 core hasn’t been made public, but I’ve heard from multiple sources who are certain for different reasons that this is indeed the case. (I wish I could be more specific, but I can’t.)”

According to Stokes, “the A4 is quite comparable to the other Cortex A8-based SoCs that are coming onto the market” except that is does away with unneeded I/O hardware.

“So if Apple just licensed the A8 and didn’t design a custom CPU core, then what was the point of the P.A. Semi acquisition? The answer to this question is still unclear,” Stokes reports. “If they were involved at all in the A4 design, and it’s still not 100 percent clear that they were, it’s likely that the P.A. Semi team made its biggest contribution to the A4 in the area of dynamic power optimization.”

“I keep coming back to the idea that Apple has stayed quiet about the A4 because any real magic or “wow factor” that the iPad delivers will come from the software—the efficiency of the OS, the user interface design of the OS and apps, and the snappiness of the overall experience all come from the software team,” Stokes reports. “In this respect, the iPad is actually a lot like the Mac.”

Full article here.


  1. Actually the A4 contains a bunch of trolls who run around inside the chip passing instructions back and forth. I’ve heard that from multiple sources and that’s all I can say for now.

    Wow, I can be a journalist too.

  2. @ @84 Mac Guy

    they said that CAN be, not that they ARE. The idea is that all you need to do to be a journalist these days is make some crap up, use a bunch of straw men (“sources say” and the like), and start a blog or website – and BAM, you’re a journalist.

    That being said, I usually enjoy Ars Technica, but this article is a bit sketchy.

    On topic – who cares if the A4 isn’t “magic”? The iPad is still going to be a great device, and I’m going to get one on launch day, even if I have to drive 50 miles (to the nearest Apple Store)!

    MW: Schools should “probably” focus more on reading comprehension…

  3. Its not that anyone is saying ‘wow I can be a journalist too’ its that they are equally as capable of writing what those supposed hacks write. If you know anything about journalism then you will know that your ability to write accurately and with knowledge on a subject has only marginally to do with your ability to get a job on a worthwhile news journal. Meanwhile the majority of those quoted as journalists here are anything but on a worthwhile news journal in the first place, they are simply people with the skills to self publicise themselves through the promotion of a web site come mouth piece over which they have influence. Rather like allowing the owners of the newspapers to write and dictate the editorial… you know a bit like Murdoch.

  4. It’s fine with me if the A4 is “nothing special.” It is the end result that counts. If the iPad can run fairly complex apps without lags and delivers good graphics performance with the strong battery life advertised by Apple (10 hours for video playback), then that is all that matters. Let Windows mobile devices try to match the performance of iPhone/iPad OS X by adding cores and upping clock speed. They will need a large battery to do so.

    If it works, then it doesn’t have to be revolutionary. Apple saves that for when it is needed.

  5. Honestly, who really gives a shit!? It could be a hamster on a wheel as long as the damned thing runs smoothly. The ONLY people that want to know specifics are the morons who want to compare hardware specs.

  6. @Michael
    You’re right. Mac users are generally more concerned with “real world experience specs.” Does it do what I need/want it to do reliably, responsively, and in an intuitive and efficient manner.

    I believe that the iPad will be a top performer in the real world experience space.

  7. OK, so the CPU is nothing special, We’re told that the impressive performance is just down to software.

    I look forward with interest to seeing others do the same.

    A 25 VA battery powers the iPad for 10 hours video playback. That means an impressively low 2.5W power consumption for the entire device including the display. Personally I think that’s very impressive and again, I look forward to seeing what the others come up with.

  8. For god’s sake this is idle speculation at this point. Perhaps we can wait till the product ships and knowledgeable people examine the internal workings to determine what the A4 chip actually is.

  9. “”So if Apple just licensed the A8 and didn’t design a custom CPU core, then what was the point of the P.A. Semi acquisition? The answer to this question is still unclear,”

    No, it’s not unclear. Steve Jobs clearly stated the acquisition was made “to allow Apple to create devices with features that can’t be copied easily by mere software updates”.

    Right now they have a few problems:
    a. they add a feature and MicroSoft copies it via a software update 3 months later.
    b. why should users pay for content through iTunes when they can rip/import/share it for free on their Mac.
    c. media companies don’t like making their products available to PCs (or Macs) because they get copied.

    Apple intends to gradually kill off the Mac while creating devices where all data is locked to the hardware …. and nobody but nobody can illegally share or modify it – all in the name of security, reliability and quality – but really just to placate media mogul fears and ensure the money flows into their media distribution coffures. This is exactly what the new iPad is aiming for, and why is does not have typical USB ports etc. It’s always about money, and if you eventually lose the freedoms you have now on your basic PC, so much the better for them. It creates what they love the most, a captive market.

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