For years, almost a decade in fact, we've been asking for higher quality displays in notebooks. With most of our pleas left ignored for the value notebook segment, smartphone and eventually tablet makers capitalized on the opportunity. These days the $399 - $499 tablet display experience tends to be superior to the $399+ notebook experience. Things are beginning to change, but not quite fast enough. At the forefront of driving tablet display performance is Apple with its Retina Display equipped iPad. While the company has never really competed in the low-cost notebook or netbook market directly, the iPad has been Apple's solution for consumers who want a computer at a $500 - $700 price point. By focusing on areas that have been neglected by PC makers in the past (e.g. display, wireless connectivity, ease of use), Apple has managed to be quite successful in this space with the iPad.

As a big part of its overall strategy, Apple has done a good job of issuing regular updates to the iPad family since its initial unveil in 2010. Now, just seven months after the release of the 3rd generation iPad, Apple followed up with a 4th generation model. It's the relentless execution cycle in addition to focusing on the integration of high quality tangibles like the display that has made the iPad a formidable competitor in the $500 - $700 consumer computing space. The iPad remains mostly a content consumption device (with a dash of productivity), although Apple has been trying to fight that stigma as of late. Your personal balance between consumption and production of content will determine whether or not the iPad can serve as a primary computing device or if it will simply augment what you already have.

As the 4th gen iPad maintains the same price point as its predecessor, Apple simply delivered a better iPad alongside the new iPad mini earlier in the quarter. Unlike the mini where the bulk of the innovation remained in the form factor, the 4th generation iPad keeps its improvements mostly under the hood. The form factor and chassis haven't changed at all since the previous generation. Apple's 4:3 aspect ratio remains ideal for portrait mode reading, although it does fall short of newer 16:9 designs when it comes to watching movies (the latter tends to be a bit awkward for portrait use in response, tradeoffs are fun).

The size and weight of the chassis remain unchanged, which does mean that the iPad continues to be very portable at under 1.5 lbs (652g) but it's too heavy for comfortable one handed operation for extended periods of time.

iPad Specification Comparison
  Apple iPad mini Apple iPad 4 Apple iPad 3 Apple iPad 2 Apple iPad
Dimensions 200 x 134.7 x 7.2mm 241.2 x 185.7 x 9.4mm 241.2 x 185.7 x 9.4mm 241.2 x 185.7 x 8.8mm 243.0 x 190.0 x 13.4mm
Display 7.85-inch 1024 x 768 IPS 9.7-inch 2048 x 1536 IPS 9.7-inch 2048 x 1536 IPS 9.7-inch 1024 x 768 IPS 9.7-inch 1024 x 768 IPS
Weight 308g (WiFi) 652g (WiFi) 652g (WiFi) 601g (WiFi) 680g (WiFi)
Processor 1GHz Apple A5 (2 x Cortex A9, PowerVR SGX543MP2)

Apple A6X (2 x Swift, PowerVR SGX 554MP4)

Apple A5X (2 x Cortex A9, PowerVR SGX 543MP4)

1GHz Apple A5 (2 x Cortex A9, PowerVR SGX543MP2) 1GHz Apple A4 (1 x Cortex A8, PowerVR SGX 535)
Connectivity WiFi , Optional 4G LTE WiFi , Optional 4G LTE WiFi , Optional 4G LTE WiFi , Optional 3G WiFi , Optional 3G
Memory 512MB 1GB 1GB 512MB 256MB
Storage 16GB—64GB 16GB—64GB 16GB—64GB 16GB—64GB 16GB—64GB
Battery 16.3Wh 42.5Wh 42.5Wh 25Wh 25Wh
Starting Price $329 $499 - $399 -

Storage and wireless connectivity options also remain unchanged, with WiFi and LTE versions both available. The new iPad is really just a silicon upgrade over the previous generation model.

A Matter of Cost and Timing

When the 3rd generation iPad launched earlier this year, I was surprised to find what Apple had done when it came to its mobile SoC. For the first time since the iPad's introduction, the 3rd generation model included a significantly larger SoC compared to what was used in the latest iPhone at the time (the 4S). In order to drive its 2048 x 1536 Retina Display at reasonable frame rates, Apple needed much more memory bandwidth than the standard A5 SoC could provide. The solution was, at the time, the world's highest bandwidth memory controller for a mobile ARM based SoC. With four 32-bit LPDDR2 channels paired up with LPDDR2-800 DRAM, the iPad 3's A5X SoC was capable of a theoretical 12.8GB/s of memory bandwidth. That's not much by high-end PC standards, but unheard of in an ARM based mobile device.

Die size is partially constrained by the amount of IO around the perimeter of the die. In the case of the A5X, the wider memory interface was paired up with a doubling in the compute resources on the GPU side. Apple didn't increase CPU hardware at all, but the A5X CPU cores did enjoy a 25% higher clock frequency than in the iPhone 4S' A5 counterpart.


iPad 4 Motherboard via iFixit

The other big surprise with the 3rd gen iPad was that Apple built its biggest SoC on Samsung's 45nm LP process. Picking a process node for a new chip isn't a trivial matter. You have to balance wafer costs, yields, die size, power/performance and volume requirements that all need to be balanced. In the case of the A5X, wafer cost and volume requirements won out over die size and power/performance concerns. The result was a power hungry SoC paired with a power hungry display, both of which necessitated an increase in battery capacity.

Simply addressing moving the SoC to 32nm wouldn't be enough to slim up the iPad. The Retina Display and associated backlight will both ensure a larger battery and thus thicker chassis for some time to come. There may be some room for improving the form factor, but in the near term I wouldn't expect a return to the iPad 2 thickness/weight levels.

Apple SoC Comparison
  A5 A5r2 A5X A6 A6X
Manufacturing Process Samsung 45nm LP Samsung 32nm LP HK+MG Samsung 45nm LP Samsung 32nm LP HK+MG Samsung 32nm LP HK+MG
Die Size 122.6mm2 71.1mm2 165mm2 96.7mm2 123mm2

The quick transition to a 4th generation iPad makes sense from a supply chain standpoint. While the 45nm A5X SoC could deliver the pricing and volume targets that Apple had at the time, the company has since shifted over to using Samsung's 32nm LP process exclusively in its iOS devices. I suspect cost, yields and available production finally tilted in favor of 32nm in the giant cost spreadsheet. The A6X is now roughly the same size as the original A5. Although wafer costs are likely higher, this is probably a more comfortable target than the A5X's 165mm2 die. Given the new iPad's static starting price point and increase in cost of many parts involved (Retina Display stack, larger SoC), any ability to reduce cost is likely a good thing.

The iPad 4 also adopts Apple's new Lightning connector. In the iPhone 5 and iPad mini, the move to the Lightning connector was done in pursuit of a thinner form factor. With the iPad 4 this obviously isn't true, but that isn't to say there aren't other benefits. I suspect moving all new production away from 30-pin dock cables and over to Lightning cables is also good for the bottom line (and for bringing Apple's cost of Lightning cables down).

The quick release of the iPad 4 wasn't all about bringing costs down however. Apple also used it as an opportunity to continue to drive performance. Similar to the A5/A5X divide, the 4th generation iPad features an A6X SoC - a larger, upgraded version of the A6 SoC used in the iPhone 5.

Display Analysis
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  • cheinonen - Thursday, December 06, 2012 - link

    Color quality has always been a target, just not one that was possible for us to easily measure before. Now that we can, it's in almost every review. If that seems to favor Apple, that's only because other vendors refuse to care about it, and they aren't going to start caring until consumers understand and demand better. Reply
  • ltcommanderdata - Thursday, December 06, 2012 - link

    It's not that pixel density is no longer important. It's that Apple has already satisfied people's needs for high pixel density. Most people already won't notice individual pixels on the iPad's 264 dpi display. So either Apple continues to improve pixel density for very little actual benefit, stops improving displays altogether, or they find another aspect of displays to improve. I think most people will be happy Apple choose the latter option and are improving color gamut and calibration. Reply
  • bplewis24 - Thursday, December 06, 2012 - link

    I'm glad somebody else notices this. Taking a page straight out of Apple's Marketing dept. Reply
  • teiglin - Thursday, December 06, 2012 - link

    Does Apple actually market their products this way? It's not like he's harping on it, but the S.S. Pixel Density set sail a year ago and all the high-end tablets are sufficient for most people (even the TF700, in my opinion--the steps from that to the iPad 4, then to the Nexus 10, are fairly incremental). Apple continues to differentiate its displays with proper calibration, and Anand is just pointing that out. As displays get better, it requires more attention to find the differences.

    The color accuracy on the Nexus 10 is objectively bad. I say this as someone who wants Google to step it up in this area--I have a Samsung tablet and my primary phone is HTC and have never owned an iPad or a Mac. Superior color accuracy isn't going to make me buy an iPad, but a dE over 8 on the Nexus 10 does make me think it's worth waiting for the generation of Google tablet.
    Reply
  • bplewis24 - Thursday, December 06, 2012 - link

    Check out their marketing materials and yes, even some of their commercials. When the coined the term "retina display" they immediately began publishing PPI measurements (and comparisons) in their marketing materials. The reason why this is significant is because other displays eventually caught up and surpassed in sheer resolution, but because the iPhone was smaller, the PPI measurement still stayed on top...even though, ironically, the benefits of such a high PPI and a much smaller display are harder to benefit from. Reply
  • cheinonen - Thursday, December 06, 2012 - link

    The value of PPI has nothing to do with screen size, but distance relative to PPI. Just like an 84" 4K LCD has benefits if you sit 5' from it but no benefit if you are 25' from it compared to a same size 1080p display. The half-inch viewfinder of the camera I just bought has a 2.4 million dot OLED display. If that used the same PPI as a retina iPhone, with 3 dots per pixel, then that viewfinder would only have 0.2 million pixels and would certainly not be as sharp.

    However, as my eye is literally right next to that, a resolution way beyond 300 PPI is useful, despite the incredibly small size of the display. It's all about the distance relative to the PPI, not the size of the screen.
    Reply
  • teiglin - Thursday, December 06, 2012 - link

    I wasn't asking if they market PPI; I know that's the theme of the whole "retina" marketing. I was asking if they market the color accuracy and how their calibration is better than the competitors'. I've seem them mention the iPad's gamut (albeit briefly) but never its accuracy or calibration. Reply
  • EnzoFX - Thursday, December 06, 2012 - link

    That's called avancement. The basis of technological progress. There Should always be something better to pursue. That is good for everyone. No matter how much your bias against Apple is. Reply
  • cheinonen - Thursday, December 06, 2012 - link

    One more note on this. CalMAN 5 is used for measuring smartphones and tablets (and likely monitors in the future) since it supports measuring grayscale, gamut, saturations, and Gretag Macbeth charts, at any targets that we want, and with manual patterns instead of only internal pattern generators. Most solutions only allow for internal generators, which is why previous tablet and smartphone reviews (many of which were done well before Apple made a deal out of this) lack these charts as those programs don't run on an iOS or Android device.

    CalMAN 5 wasn't even released until September of this year, making most of these measurements impossible to do before then. So you can enjoy the conspiracy theories, but had these measurements been possible for me to do 18 months ago, I'd have done them 18 months ago.
    Reply
  • JarredWalton - Friday, December 07, 2012 - link

    On a related note, we've been discussing the importance of color accuracy on our LCD and laptop reviews for... oh, let's see... May of 2007.
    http://www.anandtech.com/show/2237

    You'll notice that of all the laptop manufacturers, only Apple is consistently getting the display quality right (or at least, more right than others) for the MacBook Pro. And even that took a few years after my rant.
    Reply

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