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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  • darkcrayon - Friday, December 07, 2012 - link

    Ok that was pretty funny. "When you need paper that gets stuff done".

    Most documents in existence electronically are closer to a 3:4 aspect ratio. I'm sorry, but it's true. And they will fit an iPad sized screen more conveniently. But please, feel free to show me the treasure trove of ready made documents that are 9:16 or even 10:16 long.

    Also, show me the benchmarks where the Nexus 10 GPU is better than the iPad 3 - not that that disproved my point. The one in the iPad 4 is quite a bit more powerful, so it's a legitimate area where the Nexus 10 is *not* a "much better tablet". And of course don't even get us started on 10" Android tablet apps.
    Reply
  • ltcommanderdata - Thursday, December 06, 2012 - link

    Any estimate on the SGX554MP4 clock speed? Since the 16% pixel fill performance difference is supposed to be largely clock speed related and the iPad 3's SGX543MP4 was clocked at 250MHz, that works out to 290MHz. Previous Apple SoC used a 4x multiplier between CPU and GPU. If the A6X changed to a 5x multiplier, then a 1.4GHz CPU works out to a 280MHz GPU, which seems to match what is being seen here.

    And process improvements for SoC power and thermals don't have to wait for 20 nm. Samsung has a 28 nm process, which they claim uses the same design rules as their 32nm process allowing a quick and easy transition, while offering power or performance benefits over their 32 nm process. I'm guessing 2013 iDevices will use a combination of shrinks and new SoC on the 28 nm Samsung process, which with all the TSMC rumours, may be the last SoC Apple makes with Samsung. 2014 iDevices would then use TSMC 20 nm.
    Reply
  • Krysto - Thursday, December 06, 2012 - link

    So it seems that in terms of gaming performance (which is really what matters when you evaluate a GPU), the devices compare as it follows:

    Ipad 4, Nexus 4 and iPhone 5 have the same performance in games - compared as devices, running at their own native resolution.

    http://images.anandtech.com/graphs/graph6472/51760...

    As for the GPU's themselves, it seems the A6X GPU is 42% faster than Mali T604, while Mali T604 and Adreno 320 are about 10-20% faster than the A6 GPU (iPhone 5), and than the A5X GPU (iPad 3)

    http://images.anandtech.com/graphs/graph6472/51761...
    Reply
  • coder543 - Thursday, December 06, 2012 - link

    from one perspective. Honestly, benchmarks are just benchmarks. I'd agree with that assessment as far as these benchmarks go though. I'm not sure how much it matters -- suffice it to say they're all very fast. Reply
  • Alucard291 - Sunday, December 09, 2012 - link

    Very slow surely? As this is STILL about 10 years behind desktop gpu's Reply
  • ltcommanderdata - Thursday, December 06, 2012 - link

    Well the Nexus 4 having the same gaming performance as the iPad 4 and iPhone 5 depends on how often people take their phone into a freezer to play games. Reply
  • michal1980 - Thursday, December 06, 2012 - link

    amazing. Apple must be paying for this coverage, and it was a week or two ago I was told that something was coming soon.

    should have figured, another sligthly updated apple product
    Reply
  • darkcrayon - Thursday, December 06, 2012 - link

    Just as we should've figured you'd be in the comment section whining about it ;) Reply
  • vision33r - Thursday, December 06, 2012 - link

    Why would Apple be interested in marketing to PC enthusiasts on a site like this? It's a waste of money if they did pay Anand.

    In case you ever opened a male or female fashion mag or financial magazine, Apple advertisements are everywhere. Clearly they are more interested in marketing towards rich casual computer users.

    So your theory of Apple paying for this coverage as usual trolling and Apple hating. That's ok, they don't mind you hating them on a website they have little interested marketing on.
    Reply
  • pliablemoosethebanned - Thursday, December 06, 2012 - link

    Yep, Anand needs to focus more on crap products like the Surface tablet. Reply

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