Regarding Apple A4 Using iPhone 3GS Cortex A8 Processor

Apple A4 chip

The interwebs are once again lit up with speculation about the iPad's new Apple A4 chipset, this time because Ars Technica is saying that instead of the next-generation multicore ARM Cortex A9 unveiled at CES 2010, the iPad is using a variation of the last-generation AR Cortex A8 that powers the 2009 iPhone 3GS.

This is based on 1) Apple being secretive about the chipset and not bragging like other companies would 2) "multiple sources who are certain for different reasons that this is indeed the case."

First things first. Apple being secretive proves nothing. Apple is secretive about everything, and they've said before they don't discuss chipsets because they don't think it matters to consumer electronics users (and, hey, Apple is secretive). They didn't talk at all about the iPhone 3GS chipset -- all they said is it was twice as fast. We only know that it uses an ARM Cortex A8 because people bought it and tore it apart to find out.

As to the multiple sources, if one of the "different reasons" is direct knowledge of the chipset, then they could be exactly right. If not, then... eh, maybe, but we're back to waiting for the iPad to ship and people to tear it down.

In the interest of being complete, however, Ars speculates that if the iPad is indeed running the Cortex A8, this might be what's making it so fast:

it turns out that the the A4 is a 1GHz custom SoC with a single Cortex A8 core and a PowerVR SGX GPU. 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.)

In all, the A4 is quite comparable to the other Cortex A8-based SoCs that are coming onto the market, except that the A4 has even less hardware. The iPad doesn't have much in the way of I/O, so the A4 itself can do away with the I/O that it doesn't need. In contrast, the typical Cortex A8-based SoC has more I/O hardware than a mobile phone can use, because you never know what customers will need which interface types.

Ars, like Venture Beat, also thinks Apple's PA Semi team may not be involved in the iPad because they're working on a variant for the 4th generation iPhone. Either way, they believe software will ultimately be more important than hardware -- which is something Apple's been saying for a while now.

So, do we care if the iPad has an ARM Cortex A8 rather than a Cortex A9? Do we want Apple pushing the hardware, or are we happy with them prioritizing software?

Have something to say about this story? Leave a comment! Need help with something else? Ask in our forums!

Rene Ritchie

EiC of iMore, EP of Mobile Nations, Apple analyst, co-host of Debug, Iterate, Vector, Review, and MacBreak Weekly podcasts. Cook, grappler, photon wrangler. Follow him on Twitter and Google+.

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Reader comments

Regarding Apple A4 Using iPhone 3GS Cortex A8 Processor


I don't think it's possible today to have an all-day battery life in a portable device without extensive optimization of the OS and hardware. From what I've read recently, the two main obstacles to creating more and more portable devices are the size limitations of current technologies in memory storage and in batteries. That is, until these two areas of technology see some kind of breakthrough, they will be limiting factors. If it's true that the iPad can play 720p video and/or surf the internet for 10 hours (officially it's "up to 10 hours"), given the weight of the iPad, there's some serious power efficiency in the A4 chipset. The speed of the UI of the iPhone OS alone speaks to the efficiency of the chipset.
I actually don't think the A4 is extraordinarily different from the iPhone 3GS chipset. It has to have hardware compatible with OpenGL ES 2.0 and run the same basic iPhone OS.

Its easily possible to achieve All-Day battery life WITH optimization. The fact that the current iPhone just barely eeks out 24 hours (if not used much) was a deliberate design decision.
The decision was based on style, not necessity. If you increased the depth of the the iphone by 2mm, and built a custom freeform battery pack you could easily get two, maybe three days out of the device in a space that very little bigger than what is used now.
In the iPod you have fewer space restriction problems, and could pack the device with batteries in multiple locations.
It may well be that the A4 simply appears to be single core, by having the OS use one core, and setting affinity to the other core for ALL applications. In such instances, applications can not tell that there is another core.
Alternatively The A4 may be just enough of a modification of the A8 to hold them over till they feel the OS is ready to handle the A9. Throwing an OS optimized for a single core into a multi-core chipset is seldom efficient, even when it might be slightly faster.
The single most obvious lesson to be learned here, is that those who rush in and buy an iPod right away will, within less than a year be regretting the decision, and handing down hardware to their wife (who always seems to get the gadget hand-me-downs).
Wait for the front facing Cam? Wait for the REAL processor, not the stand-in? Wait for an OS tailored for this device rather than one cobbled together?
Nah! Damn the lessons learned, Disregard historical disappointments, Fanboys full speed ahead.

I am concerned with hardware more than software at the moment unless iPhone 4.0 is much more effeciant. Because I want something to open and load right when I touch/click it like it does on my pc. I know this is asking alot from a mobile device but I think they can pull it off.
My iPhone 3g is so slow opening newer apps it almost makes me want to upgrade to a 3gs now. But I'm still holding out for g4 in June.

@icebike: I think Apple has the best optimization in general, but I agree with you that Apple is more concerned about sleek design at the expense of battery life. The iPod Touch is really unnecessarily thin, IMO. There's also some cost savings in reducing the the battery capacity. But probably most importantly, Apple is so far ahead in offering a fast, optimized UI/OS/hardware combination that they don't have to offer a much longer battery life with the iPhone. They just have to make the iPhone's battery life as good as or better than the competition. The Droid is the first phone that I can think of that offers a really competitive battery life.
Incidentally, part of the reason I think the A4 is very similar to the chipset in the 3GS is also because of the relatively short amount of time PA Semi had to work on it, as well as the need to make the OS basically the same as the one on the iPhone and iPod Touch. It will be interesting to see how PA Semi's chipsets continue to progress, although I'm afraid we won't have very much detailed information about them.
Finally, I think most people who will buy a 1st generation iPad have already figured in the hand-off as a part of their plan to buy the 2nd generation iPad as soon as possible.


Finally, I think most people who will buy a 1st generation iPad have already figured in the hand-off as a part of their plan to buy the 2nd generation iPad as soon as possible.

That may be fine for people like Rene or other bloggers, who get their units paid for by TiPB or can take them as tax right-offs.
But the millions of blue-haired little old grandmothers that get this thing gifted to them or relatively naive cult-users who will buy anything Jobs holds up are going to get burned.
Remember the hue and cry when people discovered they couldn't get their 3G upgraded to 3GS without paying full price?
No, I don't believe anyone other than a few gadget geeks realize how ahead of time just short lived and under-powered the first version of the iPad will be.
The problem with a fan-blog like this one, is that this idea is NOT being discussed. This sets up a whole new generation of victims. I understand that the blogs (not only TiPB) have to remain on the good side of Apple, but after a while you would expect at least a few nuggets of integrity to remain in the bottom of the cup after all the koolaid is gone.

Boy, I murdered that 4th paragraph:
Meant to say:
No, I don’t believe anyone other than a few gadget geeks realize ahead of time just how short lived and under-powered the first version of the iPad will be.

That's a fair point about bloggers feeling the money sting less on these devices due to write-offs, but we will discuss the ROI as the launch gets closer. I felt if we did it early it would be forgotten when actual buying time rolls around. We traditionally do a writer vs. writer, to buy or not to buy double post for those.
Personally, however, I still love my iPhone 2G (that I paid a fortune for to get unlocked from across the US border -- before I worked for TiPb and just because the interface was so "wow"). I don't know if the iPad G1 will age as gracefully, but I know my mother or sister or godsons would love any hand-me-downs that come their way next year.
$500 over the course of a year's use is relatively little. Less than $50 a month. Many pay more than that for Startbucks. That's why we cover ROI and not TCO ;)

I agree the price is not outlandish, And I solved my Starbucks problem with one of these
I'm looking forward to a fair Buy/NoBuy article. If it happens sooner rather than later perhaps we could convince Apple that front facing Camera is crucial.
But unless Apple decides to seed the blogosphere with evaluation machines none of the Camp-out-overnight crowd will have a clue about what they are buying, how fast, how limited, how controlled.

for me timing is everything and I have a need for something between my laptop turned home server and my iphone which has become my pc. for me limited controlled or whatever it fits the bill and i wont mind when a faster one comes out in a year. with Tech you can wait forever and never get it or be happy with what you get and hand down to the wife :).