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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softdrinkviking - Thursday, April 8, 2010 - link
it occurs to me that i would want a way to protect the screen from getting scratched, and that would mean acover or case that would take the place of the clamshell design of a netbook/notebook.
why would i want to pay a price premium for a device with slower performance which only achieves acceptable functionality with the addition of expensive peripherals?
even after all the peripherals, i still lose the ability to effortlessly prop-up a netbook on my lap and type an email, or set a netbook up on a table in a coffee shop.
nothing about the tablet form factor is convenient for on-the-go usage for me.
the only situation where i can possibly imagine this being a preferable form factor is for wall mount usage or some other kind of "always left out in the open" type of use, like a universal remote control, or a mini home television viewer in the kitchen.
but it seems too expensive for those uses to me.
there must be a better alternative.
MacTheSpoon - Thursday, April 8, 2010 - link
Thanks for the great review. I was shocked you'd typed 40% of it with the iPad.Would you mind doing a comparison between the iPad keyboard and a physical keyboard? Since there is no utility to measure WPM for the iPad, maybe you could time how long it takes to type the same passage on both--something with some semicolons, quotation marks, and/or em dashes would be ideal, as I'm curious how the virtual keyboard stands up when the user must switch between layouts.
Brian Klug - Thursday, April 8, 2010 - link
You know, this was something I was dying to address a few times. I'm hoping that the iTextspeed application developers update their code soon to be iPad compatible, because that's something I want to test for sure.I've gotten to the point where I can touch type in landscape pretty easy, but I can also type pretty fast on the iPhone (around 80 WPM using their application). If and when it's updated, we might do something and include the update.
If it helps any, this was also composed pretty quickly from an iPad. ;)
Cheers,
Brian Klug
solipsism - Thursday, April 8, 2010 - link
1) How did you get a 720p video on the iPhone for the video test when the allowable maximum "up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second" video?2) From my testing, the iPad uses about 20MB more than the 3GS on startup. Most, if not all, of this is for the GPU. I've also noticed that native apps are also using more RAM. While the 3GS has enough to support standard multitasking the iPad does not. Even switching pages in Safari on the iPad would have to be reloaded while the 3GS does not. This will even more of an issue with the 3G version of the iPad. This gives me doubts about multitasking unles iPhone OS v4.0 is much more efficient (making 3.2.2 a stand in, which looks to be the case) and Apple has a more intuitive quasi-multitasking concept to unveil today.
Brian Klug - Thursday, April 8, 2010 - link
I can't speak about the RAM usage - are you using iStat or similar?However 720P H.264 video is certainly supported, which is what we used. I tested all the different profiles in handbrake, all of them work if you keep the video at or under 1280x720:
"H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format"
That's straight from http://www.apple.com/ipad/specs/
I think you're getting confused with the MPEG4 limitation which is indeed 640x480. ;)
-Brian Klug
Ph00 - Thursday, April 8, 2010 - link
sorry to be ot but is that a black mouth cur dog?Griswold - Thursday, April 8, 2010 - link
I'll wait for iPad v2 with reliably working wifi, no overheating, working PDF export, at least a backside camera for snapshots and maybe short flicks and perhaps multitasking. Ill stop here because any more missing features would seem greedy - apple needs a reason to sell you the 2012 iPad...As for atom based ipad - are you nuts? Nobody wants that garbage. Gimme a dual core cortex A9 instead.
Mike1111 - Thursday, April 8, 2010 - link
You mean the 2011 iPad, right? Because there's no way Apple isn't gonna do a yearly refresh cycle like they do with all their iPhone OS based products.Mike1111 - Thursday, April 8, 2010 - link
My mistake. You meant even iPad v2 in 2011 won't be feature complete because Apple needs some features for the 2012 iPad v3.Hm, how do I delete a post?
Lemonjellow - Thursday, April 8, 2010 - link
"Sure, but so could a TV that made me pancakes. Neither is ready yet or guaranteed."Can you confirm or deny that someone is working on said TV project? :- D