The Display

The most visible improvement of the new iPad is naturally its Retina Display. Originally introduced with the iPhone 4, the concept of an Apple Retina Display was created to refer to a display where the pixel density was high enough that the human eye, at a standard viewing distance, could not resolve or identify individual pixels.

Unlike traditional OSes, iOS doesn't support a laundry list of display resolutions. The iPhone was introduced at 480 x 320 (3:2 aspect ratio), while the iPad came to be at 1024 x 768 (4:3 aspect ratio). Rather than require iPhone applications be redesigned for a higher resolution iPhone, Apple simply doubled both the vertical and horizontal resolution for the iPhone 4—maintaining the same aspect ratio as the previous models, and only requiring higher quality assets, not a redesigned UI, to take advantage of the new display.

The iPad on the other hand always required a redesigned UI to make the most of the iPad's larger display and higher resolution. With a different aspect ratio, simply scaling up an iPhone app wouldn't work (although to enable backwards compatibility Apple did allow you to do just that). Admittedly Apple wouldn't want to allow such easy portability between iPhone and iPad apps as it wanted the extra effort to improve the quality of tablet apps.

The new iPad does what the iPhone 4 did and doubles both horizontal and vertical resolution: from 1024 x 768 to 2048 x 1536. All iPad applications work by default as developers don't directly address pixels but rather coordinates on the screen. Existing apps take up the full screen, and if higher resolution images are present they are used as they avoid the interpolation associated with scaling up an image designed for the original iPad resolution. For example, below we have a makeshift iOS icon in three different forms—10x7 native (72x72), upscaled to a 2x version using bicubic interpolation (144x144), and a 2x resolution version (144x144):

144x144 (Upscaled)
144x144 (Native)

The upscaled form looks good, but the 2x resolution version looks better.

More traditional OSes have always given you additional desktop real estate with increased resolutions. iOS simply gives you a better looking desktop. This distinction is arguably one of the reasons why the new iPad's display can be so polarizing. As consumers of high-end displays we're used to higher resolution going hand in hand with a larger panel size. Alternatively, we're used to a higher resolution enabling us to see more on a screen at one time. In the case of the new iPad, the higher resolution just makes things look sharper. It's a ton of work for an admittedly more understated impact, but it's the type of thing that simply had to be done.

Retina Display Enabled Apps

Apple has created such a healthy marketplace with the app store that developers are eager to quickly deliver apps with updated graphics for the new iPad. Sure enough, by the day of launch we saw several high profile applications with higher resolution assets for the new iPad. The motivation to have Retina Display support is huge as Apple is actively promoting those apps that have been updated for the new iPad via the app store:

These updated apps now come with larger image assets, which can increase the total app size. Not all apps will grow in size (e.g. Infinity Blade 2 simply renders at a higher resolution vs. using tons of new content, not to mention that textures are already heavily compressed) but some have/will. The retina burden unfortunately impacts all iPads as there's only a single app package delivered upon download. Even if you don't use them, the higher resolution retina graphics are there.

Note that iPhone apps will now load their Retina assets (designed for 640 x 960) rather than their normal assets (designed for 320 x 480) on the new iPad, resulting in a significant improvement in image quality there as well:

Games are a special exception to the 2x asset scaling of the new iPad. Applications that simply have their UI accelerated by the A5X's GPU do fairly well at the iPad's native resolution. 3D games are another story however.

If all you're doing is determining the color of a single pixel on the screen, not impacted by lights in 3D space or other transparent surfaces above the surface, it's a relatively simple and painless process. For the majority of what you're looking at in iOS, this is simply the procedure. The app instructs the drawing APIs to place a red pixel at a set of coordinates and that's what happens. In a 3D game however, arriving at the color value of that pixel can require quite a bit of math, and quite a bit of memory bandwidth.

Game developers have a few options on the new iPad. One option is to not update a game, running it at 1024 x 768 and rely on the iPad's scaler to upscale the image to 2048 x 1536. The game will take up the full screen, run faster than on the iPad 2, but it won't necessarily look any better. Low resolution content upscaled to a higher resolution display still maintains much of the aliasing you'd see at a lower resolution.

Another option is to render all scenes at the new iPad's resolution: 2048 x 1536. With four times the number of pixels to fill and only 2x the compute and memory bandwidth compared to the iPad 2, this will only work for fairly lightweight content. Not to say that it's impossible—even GLBenchmark's Egypt test, in its current form, actually runs very well at the new iPad's native resolution. Many stressful 3D games won't fall into this category however.

The third, and more popular option is for a game developer to render all frames offscreen at an intermediate resolution between 1024 x 768 and 2048 x 1536, then scale up to the panel's native res. So long as the developer maintains aspect ratio, it'll be possible to use this approach and get a good balance of higher resolution and performance.

Infinity Blade 2 for the new iPad Renders at roughly 1.4x the iPad 2's resolution, then upscales to fill the screen

Infinity Blade 2, for example, renders offscreen at roughly 1.4x the resolution of the iPad 2 before scaling up to 2048 x 1536 for final display. The result is a sharper image than what you'd get on an iPad 2, without sacrificing performance.

Game developers may choose to increase the level of anti-aliasing instead of or in combination with an increase in resolution. As we'll discuss shortly, Apple's A5X does come equipped with more GPU execution resources and dedicated memory bandwidth for graphics that would allow for an increase in quality without a corresponding decrease in frame rate.

The new iPad The Display: In Numbers
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  • jjj - Wednesday, March 28, 2012 - link

    Testing battery life only in web browsing ? Maybve that would be ok for a 100$ device.As it is the battery tests are prety poor,you do video playback when every SoC out there has a dedicated decode unit and that test is only representative for vid playback.Here the most important test should have been battery life when both GPU and CPU are loaded and not including that seems like an intentional omission to avoid makiing the device look bad.
    There are a lot of other things to say about the review,too many but one thing has to be said.
    This is a plan B or plan C device.The screen is the selling point,is what had to go in,they didn't had 28/32nm in time and had to go for a heavier,thicker,hotter device with a huge chip (CPU speed is limited most likely by heat not so much power consumption,ofc both are directly related).Apple had to make way too many compromises to fit in the screen,no way this was plan A.
  • tipoo - Thursday, March 29, 2012 - link

    I would have liked a gaming battery life test as well.
  • PeteH - Thursday, March 29, 2012 - link

    Beyond even that, I'd like to see a worst-case battery life (i.e. gaming, max brightness, LTE up, etc).

    Also, it'd be really interesting to see how brightness impacts battery life. Maybe the web browsing test at 20%, 40%, 60%, 80%, and 100% brightness. Of course that would probably delay the review by several days, so it might not be worth it.
  • Anand Lal Shimpi - Thursday, March 29, 2012 - link

    We did a max brightness test, however a gaming test would be appropriate as well. I will see if I can't run some of that in the background while I work on things for next week :)

    Take care,
  • SimpleLance - Wednesday, March 28, 2012 - link

    The biggest drain for the battery comes from the display. So, if the iPad will be used for hotspot only (with display turned off), you will get a lot of hours from it because it has such a huge battery.

    But then, using the the iPad just for a hotspot would be a waste of that gorgeous display.

    Very nice review of a very nice product.
  • thrawn3 - Wednesday, March 28, 2012 - link

    Am I the only one that feels the max brightness is more important in day to day use of a highly portable device than DPI and color accuracy?
    I absolutely would love to have all of these three be excellent but I think for a tablet or small laptop Max Brightness and DPI are higher priority than color accuracy. This is exactly what the ASUS Transformer Infinity is supposed to be but I would prefer it on a real laptop.
    I care about color accuracy too but I am perfectly fine with needing a desktop monitor and trading brightness there since it is in a stable environment until we hit the technological level that will allow all these elements to be combined. Maybe quantum dot display technology in the future?

    One thing I have to give all these new displays is that they FINALLY have gotten the wide viewing angles thing right and I will be so happy to get this into the rest of the market.
  • seapeople - Tuesday, April 3, 2012 - link

    Would you really prefer a bright 1366x768 TN panel with 200 contrast ratio on a 15" laptop over a less bright IPS Ipad screen with much better resolution, DPI, color accuracy, and viewing angle?
  • vision33r - Wednesday, March 28, 2012 - link

    The screen is really gorgeous when you shoot raw with any DSLR and view it in iPhoto.
  • ol1bit - Wednesday, March 28, 2012 - link

    I just bought a Asus Transformer Prime, and your review was spot on with what I decided. I can not live with IOS and using Android for 3 years.

    Just the simple stuff was my decision:
    1. Freedom of Android, file transfers, etc. No Itunes requirement.
    2. MicroSD
    3. Kewl keyboard
    4. Live Wallpaper.
    5. A real desktop, separate from my applications.
    6. 32GB versus 16GB
    7. Gorilla Glass (yes, true. My original droid lived in my pocket 2 years no scratches, my HTC Rezound scratches the first 2 weeks).
    8. Asus (love their MBs)
    9. Nivida (love their GPUs)

    What I will miss:
    1. Ipad 3 Display.
  • darkcrayon - Thursday, March 29, 2012 - link

    1. iTunes is no longer ever needed for an iOS device. I consider the option of a first party desktop sync solution to be an advantage now that it's not a requirement.
    7. It seems likely the new iPad uses Gorilla Glass or Gorilla Glass 2...
    9. Odd that you'd love nVidia's GPUs when they've been pretty much the bottom of the performance barrel for ARM device graphics, even excluding Apple's SoCs (which have lately been using the fastest GPUs in the industry by far).

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