Apple's iPad - The AnandTech Review
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on April 7, 2010 9:39 PM EST- Posted in
- Smartphones
- Mac
- Apple
- iPad
- Mobile
The Silicon - Meet the A4
Before the first iPad was ever unboxed, photos had already leaked of its dissection. Admittedly, I was relieved as it meant I didn’t have to risk destroying mine to figure out how to get inside the chassis. Why was getting inside Apple’s new tablet such a big deal? Because it’s using Apple’s brand new SoC.
It’s called the A4 because it is the 4th generation SoC designed by Apple. That would make the silicon in the iPhone 3GS the A3, the A2 would be what’s in the iPhone and perhaps A1 was an older iPod chip? Either way, the A4 was the first we heard of Apple’s naming system.
For months leading up to the iPad announcement everyone assumed that Apple’s acquisition of PA Semi meant that the company was going to ditch Samsung and come forth with its own killer SoC. Would it be an out-of-order Cortex A9 design? Or would it be truly custom, similar to what Marvell or Qualcomm have done with their Armada and Snapdragon lines?
As with everything involving the iPad, rumors of the device’s silicon ran rampant. But the idea of Apple doing their own microprocessor architecture for the iPad was disappointing to me. To understand why, we have to look at Apple COO, Tim Cook’s recent statements on why Apple has been successful:
“We are the most focused company that I know of or have read of or have any knowledge of. We say no to good ideas every day. We say no to great ideas in order to keep the amount of things we focus on very small in number so that we can put enormous energy behind the ones we do choose.”
Tim was talking about products there, but I believe his statement is applicable to the A4 as well. Apple is not a microprocessor company, nor does Apple want to toss its hat in with the likes of Intel, NVIDIA, Qualcomm and TI as an SoC maker. History has shown us that the only way to be a successful microprocessor company is to be able to subsidize the high cost of designing a powerful architecture over an extremely large install base. That’s why x86 survived, and it’s why the ARM business model works.
Designing high performance SoCs just for use in the iPad and iPhone just doesn’t make sense. In the short term, perhaps, but in the long run it would mean that Apple would have to grow the microprocessor side of its business considerably. That means tons of engineers, more resources that aren’t product focused, and honestly re-inventing the wheel a lot.
The fact that the A4 appears to be little more than a 45nm, 1GHz Cortex A8 paired with a PowerVR SGX GPU tells me that Apple isn’t off its rocker. I don’t exactly know what Apple is doing with all of these CPU and GPU engineers in house, but licensing tech from the companies who have experience in building the architectures is still on the menu.
The A4 is a typical smartphone SoC. It’s got CPU, GPU and DRAM all on a single package. It also appears to be the same size as your typical smartphone SoC, meaning there’s a good chance we’ll see this thing in the next iPhone. The A4 has 256MB of on-package DRAM, just like the current iPhone 3GS SoC. Remember that memory is used for the OS, all applications as well as video memory. It’s a testament to just how lightweight the iPhone OS is.
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solipsism - Thursday, April 8, 2010 - link
I also thought the Moorestown recommendation was odd, especially when the next page was about the phenomenal battery life. If he made a more detailed case for it perhaps he'd have a point, but the simple "because it's faster" stance is lacking.Anand Lal Shimpi - Thursday, April 8, 2010 - link
Initial power specs for Moorestown appear to be fairly competitive with ARM based SoCs. Remember this is Moorestown, and not Pineview. The two chips are very different.Realistically I don't think it would be Moorestown, but the 32nm follow-on starts to make a lot of sense.
Take care,
Anand
metafor - Thursday, April 8, 2010 - link
Just curious, what are the initial power numbers for Moorestown anyway? Keep in mind that with the change in bus architecture and the use of LP DRAM, performance will be significantly slower in some cases than current netbooks. Also, would it really compare to an A9-class SoC?IntelUser2000 - Friday, April 9, 2010 - link
I have a feeling Apple didn't go Moorestown for two primary reasons.1) Timeframe
2) Cost
Moorestown should be announced shortly, but the devices based on it won't be available until Q3 of this year. That's 6+ months from when the iPad is going to release. And although Intel might achieve both better performance and comparable power usage, but the sacrifice there will be higher cost. Fully integrated SoC like the A4 costs significantly less.
Performance should be quite good. There's a 600MHz version for smartphones that can use Burst Mode to 1.2GHz, and a MID oriented version that probably clocks at 1.3GHz base and does 1.9GHz burst. It's supposed to feature "Bus Turbo" as well.
If they also do a full integrated memory controller unlike Pineview we have a good chance it'll be clock per clock faster than Netbook Atoms. Earlier on Intel claimed "30%" boost over previous platform but clock speeds weren't mentioned.
metafor - Friday, April 9, 2010 - link
Moorestown will be a fully interated SoC. It'll have LP DDR1 and LP DDR2 memory controllers as well as a GPU, the Atom CPU and various peripheral connectivity. It's comparable to the A4 in terms of features although I really would not write it off as "comparable" in terms of power until some data is published.ekul - Thursday, April 8, 2010 - link
I'd agree the successor to moorestown is more promising. Are there even any shipping products based on moorestown yet? I don't think apple is going to take a gamble on an untested platform.I'm genuinely looking forward to seeing performance numbers for cortex a9, especially since there will be real dual core mobile variants, not just hyperthreading. A technique like what MS is planning for IE9, rendering a website on one core and compiling javascript on another, would help bridge the perormance gap along with the higher clocks.
michal1980 - Wednesday, April 7, 2010 - link
really this is easier then a laptop/notebook?A notebook by its vary nature I can rest on my lap or a table and adjust its screen. To watch a movie I dont have to hold the thing up.
To type, I dont have to bend to werid angles to hold the device up, etc etc.
IMHO, it seems like alot of the experance is attributed to the newness of the device vs its actual usage. I'm wonder how this newness will wear.
manicfreak - Thursday, April 8, 2010 - link
Can't you do all of those aforementioned things on an ipod touch/iphone? There are already home automation apps for the iphone right now.What can the iPad do that the iphone/ipod touch can't? Beside having a bigger screen and longer battery life?
And for such a big device, the performance should be closer to an atom instead of a snapdragon.
If something doesn't fit in my pocket, then I would rather bring a light-weight CULV laptop with me... with touchscreen if one wishes (i.e. Acer Timeline 1820T) or a hybrid notebook-tablet (Lenovo IdeaPad U1).
jasperjones - Thursday, April 8, 2010 - link
"there are some things the iPad does much better than anything you might own today. Web browsing, photo viewing, reading email, any passive usage scenarios where you're primarily clicking on things and getting feedback, the iPad excels at."What exactly makes it better at those tasks? It's not that I disagree but, in my opinion, you didn't drive this point home. I don't understand why you think it's better. And yes, I read the whole article.
solipsism - Thursday, April 8, 2010 - link
I don't think anything anyone can write can convince you. Many aspects just feel more natural to use. That isn't to say it's perfect everywhere but I think that as a casual mobile consumption device it's much better than a notebook, and much better than a netbook.