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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  • vkn - Friday, December 07, 2012 - link

    I for one appreciate these tests. There is no easy way to judge displays in showrooms. I now have a system of playing the the same hd videos on each device and evaluating subjectively (which sucks) Reply
  • darwinosx - Thursday, December 06, 2012 - link

    You don't know anything. Apple has been doing this on displays for a very long time. Since you are obviously a teenager, probably longer than you have been alive. Reply
  • jabber - Friday, December 07, 2012 - link

    Yes funny that.

    I saw this with NFC.

    Before the finer points of the iPhone5 came out tech journos were all "NFC!!! NFC!!!! ITS THE FUTURE!!!"

    Then the 5 came out with no NFC and it was overnight a switch to "Oh......NFC isn't really all that important! Whats NFC again?"
    Reply
  • name99 - Sunday, December 09, 2012 - link

    Really? Show us RESPECTED tech journalists who were, to use your language "all NFC! NFC! NFC!" about the iPhone5.
    I don't remember Gruber obsessing about this. I don't remember Anand saying this was an essential iPhone5 feature. I don't remember Horace Dediu caring about this.

    Apple has made it quite clear, since they shipped the iPhone 4S, that they view BT4 as a better solution for most of the things that NFC is supposed to do. Given the extreme lack of interesting things being done with NFC, that seems like a good call.

    Your claim is as ignorant as being surprised that the new iMacs shipped without an optical drives.
    Reply
  • Death666Angel - Saturday, December 08, 2012 - link

    Me personally, I don't agree with Anand. The eyes are pretty good at adapting to colors. So unless you have a calibrated PC monitor or something to compare to, you will not notice when colors are off, unless they are off by a big, big margin. I haven't seen a lot of that in the android camp and when it crept up, there were easy fixes by the community. Reply
  • cheinonen - Sunday, December 09, 2012 - link

    Eyes are very adaptable to what is put in front of them, just like ears are with sound over time. That's why all the measures are done by instruments that aren't subject to the adaptability of our vision system. The dE numbers are designed to tell you how visible an error is. With the older 1976 and 1994 formulas, any dE below 3 was thought to be invisible in motion, with < 1 invisible when side-by-side. The dE2000 formula used in these charts is more accurate (in terms of weighing luminance, hue, and saturation errors), but smaller errors are more visible, so a dE of 3 is now worse than a dE of 3 in the old formulas. The dE numbers have a basis in vision science, though, and let you know if an error is visible.

    How well you'll notice, or care, about a color error likely depends on your exposure to correct colors. If you've spent years looking at a calibrated display, then you'll notice the errors almost instantly. If you've never seen one, you won't notice as you have no idea what it should look like. The whole point of calibration is just so when you see something, or design something, everyone else sees it the same way.

    Also, a global fix for color errors isn't likely to work well, as all displays are slightly different and would need to be calibrated individually. You could make some adjustments, but not make them perfectly accurate.
    Reply
  • name99 - Sunday, December 09, 2012 - link

    To add to this point, I am not an obsessive about color. I don't do design work, or know Pantone numbers by heart or anything. But it was obvious enough to me that colors (in particular photos of faces in Contacts) looked different on my mac and my iPhone 1 that I submitted a bug to Apple about it.

    This is, to put it bluntly, the difference between Apple and other people. Other (supposedly technical) people see that a photo of a friend looks slightly different on their phone from their computer --- it's a little too dark or too red or whatever --- and they shrug and say "well, it's always been like that". Apple people say "Why the hell should we put up with this? It's possible to do better." It's this mindset that leads to useful improvements based on actual use cases, as opposed to useless improvements based on spec-boasting.
    Reply
  • Focher - Saturday, December 08, 2012 - link

    Not sure what the problem is. Everything is tested and reported. It's up to you to decide which attribute(s) matter to you.

    If anything, we should really appreciate that AnandTech reviews those attributes. In addition to Apple actually making the display quality a market differentiator for vendors who play in this space, AnandTech deserves credit for ensuring we see which manufacturers are delivering improved display attributes.
    Reply
  • name99 - Sunday, December 09, 2012 - link

    It's silly to claim that Apple has "just started" promoting color calibration.

    Color calibration was added to the original Mac OS in 1993 (ie WAY before OSX) and every year since then Apple has worked to move it a little pervasively into the system as CPU and GPU speed increases have allowed for more on the SW side, and as tighter control of manufacturing have allowed for more on the HW side.
    Reply
  • sprockkets - Thursday, December 06, 2012 - link

    Screw the ipad. We want the Nexus 10 review! Reply

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