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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Anand Lal Shimpi - Wednesday, April 7, 2010 - link
I definitely appreciate the corrections :) Fixed!Take care,
Anand
odditude - Friday, April 9, 2010 - link
Bottom of P12: "Most developers just got access to the iPad on " - unfinished fragmentafkrotch - Thursday, April 8, 2010 - link
I found a bunch of errors in the article, but I chalked it up to him trying to use the iPad for actual work. Something it apparently sucks at.strikeback03 - Friday, April 9, 2010 - link
lol, I thought the article might have been a little rushed, kinda like the iPad. Great insight and content, but could have stood for a little more editing.CyberMonk - Wednesday, April 7, 2010 - link
According to Apple, you're incorrect about the iPad not having an oleophobic coating. From the iPad's tech specs page: "Fingerprint-resistant oleophobic coating"solipsism - Wednesday, April 7, 2010 - link
3rd-party accessory are allowed. Bluetooth keyboards already work with it and Apple licenses the iPod Dock Connector port so there is nothing stopping anyone else from selling their own keyboard, dock, or whatever, which I hope they do as the one Apple supplies has no option for folding down for easy travel.You can even use a simple USB-A(f)-to-USB-A(f) coupler for syncing your photos instead of paying for Apple's adapters. There are other options that already exist in this arena for USB.
Grump642 - Wednesday, April 7, 2010 - link
Think I will hold on till the HP Slate comes out. It will have most of the things on it that the iPad is missing.afkrotch - Thursday, April 8, 2010 - link
If the HP Slate runs Win7, I'd be all over it. I picked up a HP TM2, but the touchpad was broken on it. I went for a replacement, but none available. I'm waiting for more to come in stock, hopefully that's before the Slate comes out.I tend to jump right into purchases and I'd rather see how the Slate does. If it comes out before the TM2 comes in stock, that might not happen.
joe_dude - Wednesday, April 7, 2010 - link
That was a very detailed review. Only disagree on the gaming aspect. While the touch interface is cool, the CPU, GPU & memory seriously limits its potential. Others have already mention that.http://www.gamesradar.com/f/real-gamers-review-the...
Nothing against retro-gaming, but Worms, C&C, RE4, Scrabble, etc. are netbook quality at best.
ekul - Wednesday, April 7, 2010 - link
Anand,An excellent article as usual. While most of the ipad reviews have been quite through you have managed to discuss elements of the device no one else has touched on.
That said I have to disagree with your plea for a moorestown cpu. Even with moorestown being so much more efficient than regular atom based systems it can't touch a cortex a8 for idle or load power draw. Combine that with smaller packaging for arm, lower costs and true SoC designs and it isn't even a contest. The price is lower performance but I'll take the trade for battery life.
Keeping ipad the same architecture as existing iphone OS devices is a big bonus as well, lowering development costs for both apple and app developers. ARM is also providing an excellent upgrade path from a8 to the a9 SoCs that are sampling now and should be in devices shortly.
Once there is a true SoC design based on atom it might be worth considering but for now it's just not ready