The Apple iPad Review (2012)
by Vivek Gowri & Anand Lal Shimpi on March 28, 2012 3:14 PM ESTBattery Life
For a company that has been so laser focused on reducing weight and device thickness, the new iPad actually growing in both of these dimensions was unexpected. From a technical standpoint, the tradeoff makes sense. The new Retina Display consumes significantly more power than its predecessor, as do the A5X and MDM9600 baseband. Both of those ASICs are still built on a 4x-nm LP process and will surely increase power consumption over the iPad 2.
With more transistors switching on the same process node and a display (and backlight) driving more pixels at the same brightness, the battery either had to be larger or battery life would suffer. Apple understandably chose the former and the new iPad ships with a 42.5Wh battery—the largest we've ever seen used in an ARM tablet. The new iPad's battery is so large it's even bigger than what Apple uses in the 11-inch MacBook Air, and it's within striking distance of the 50Wh unit you'll find in the 13-inch model. I do believe this move says a lot about how Apple sees the iPad moving up in the world, but I'll get to a discussion about that later.
With a 70% larger battery than the iPad 2 but with more power hungry components inside, how does the new iPad fare in real world usage? Subjectively: it doesn't last as long as its predecessor. Objectively, our numbers seem to agree.
Our web browsing battery life test browses through dozens of web pages, pausing on each to simulate reading time, until the battery is depleted. All of our tests are run at the same brightness settings (200 nits) to ensure we are comparing apples to apples.
On WiFi we measured an 8% decrease in battery life compared to the iPad 2—nothing huge but not insignificant either. Fall off of WiFi and depend on LTE and you'll see around a 9% decrease in battery life, again—noticeable but not unusable.
I also threw in numbers from the Motorola Xyboard 10.1, an LTE enabled Android tablet running 3.2. Equipped with a much smaller battery (~26Wh), the Xyboard 10.1 delivered 7.31 hours in our LTE web browsing test. The new iPad managed to last 16% longer on a single charge—a smaller advantage than you'd expect given the 70% increase in battery capacity, showing just how much power the new Retina Display and its backlight consume.
The iPad is more than usable on long flights or throughout the day without being tethered to a wall outlet, but in practice you can expect a decrease in battery life compared to last year's model.
Keep in mind that these values are all at 200 nits (roughly 70% brightness on the iPad). If you use the iPad at max brightness (~400 nits) you'll see considerably lower numbers:
In our web browsing test, at max brightness, we saw 5 hours and 34 minutes of continuous use before the battery died. The iPad 2 incurs a similar penalty, lasting under 7 hours in the same test. Do keep this in mind if you need to get a lot of untethered use out of the new iPad. In order to come close to Apple's battery life estimates you'll have to be below 70% brightness.
Charging
Despite the significant increase in battery capacity, Apple continues to ship the new iPad with the same 10W USB power adapter as the previous two models. You can charge the iPad via a Mac/PC USB port that implements the USB charging spec, however doing so will take a minor eternity to fully charge the tablet. Just as before, the new iPad will not charge off of a USB port if the tablet is awake; it will only charge when locked/asleep. The convenience of having a USB based charger is evident, but you'll want to stick with the 10W adapter to actually charge the iPad.
Charging the larger battery does take longer. If we measure from a completely dead state to when the iPad indicates that it's fully charged the increase in time is approximately 50%, from 4 hours with the iPad 2 to 6 hours with the new iPad. ASUS' Transformer Prime, by comparison, requires only 2.5 hours as it ships with an 18W charger. And no, you can't use ASUS' charger to speed up charge times on the new iPad—when connected, the TF Prime charger will only supply 9W to the iPad.
The story doesn't end there however. While the iPad 2 will draw 0W after its 4 hour charge cycle is complete, the new iPad will continue to draw around 3W after it claims to be fully charged. This will continue for roughly another hour at which point the power adapter will draw anywhere from 0.1—0.6W.
Note that when running at full brightness and with a heavy GPU load (e.g. Infinity Blade 2), the power adapter can't supply enough to keep the iPad charged and drive the display/internal components.
There's no good solution here other than for Apple to start shipping the iPad with a higher wattage power adapter. I do believe faster charge times are going to be necessary if Apple is keen on sticking with this larger battery, not to mention the usage issues of not being able to maintain charge equilibrium under load.
Thermals
The increase in power consumption of the new iPad also manifests in the form of increased heat production. A 163mm^2 SoC built on a 45nm LP process is a serious chip. Although it doesn't run hot enough to require active cooling, the SoC alone is responsible for a couple of watts of the iPad's TDP under heavy load. Combine that with a 45nm LTE modem and the heat put off by the more powerful backlight and you've got a recipe for a noticeably warmer device.
Does the new iPad get warmer than the previous one? Absolutely. I would even go as far as to say that it can get uncomfortably warm, but it never gets too hot to hold. If you've used any of the modern Mac notebooks, I don't believe it's anywhere near as bad.
When holding the new iPad in portrait mode, with the home button at the bottom, the lower left corner of the device ends up being the warmest. Along the left edge of the iPad is where the logic board resides, and the lower half is home to the A5X SoC. Under load, particularly a heavy GPU load (e.g. playing a 3D game), this area is going to heat up quickly.
I took several measurements using a contactless IR thermometer in the same ambient conditions on a new iPad vs. the iPad 2. The results are below:
| Thermal Comparison (Max Temperature) | |||||
| iPad 2 | iPad (3rd generation) | ||||
| Web Browsing (2 hours) | 32.7˚C | 37.6˚C | |||
| Infinity Blade 2 (1 hour) | 34.2˚C | 41.9˚C | |||
Again, I don't believe this is a deal breaker but it's the obvious result of remaining on Samsung's 45nm LP process combined with a more power hungry display/backlight. I suspect there will be improvements in efficiency on the display side over time, but I can't see the Retina Display being any lower power than the iPad 2's 1024 x 768 screen. The real avenue for improvement will be when Apple shifts to 28/32nm silicon for the SoC and LTE modem. If you want a cooler running iPad, you'll have to wait until next year for that.
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Anand Lal Shimpi - Thursday, March 29, 2012 - link
Max brightness.Take care,
Anand
h4stur - Thursday, March 29, 2012 - link
I use it every day. But it don't see enough improvement in the new version, to warrant an upgrade. I view the high ress as an actual downgrade. As the machine will have to upscale the majority of the content.mavere - Thursday, March 29, 2012 - link
text text text text.If that means nothing to you, then the upgrade won't do anything for you. For the rest of us, this screen is a godsend.
darkcrayon - Thursday, March 29, 2012 - link
I'm guessing the machine will have to upscale very little content other than images on the web in a month or two. Every major app will be updated for the higher resolution, no new app will be caught dead not supporting the new resolution, and text based apps get a "free" upgrade to the higher resolution. If your primary concern is whether images on the web will be updated, then that's an area for disappointment. Otherwise...adityarjun - Thursday, March 29, 2012 - link
I love this site and most of the reviews. Since the ipad has been released I have been coming here 6-7 times a day just for this review. Glad to see it finally put up. I just registered here specifically to ask a few questions.While I was more than impressed with the review, I was hoping to read something about the use of Ipad as an educational tool. This section was sadly missing.
I am a engg grad student and I am currently looking for a good pdf reader. The only viable options for me are the new Ipad or the Kindle DX (the kindle 6" is too small). While the Kindle does sound good , the problem is that some of my pdf books are over 100mb and full of mechanical drawings. Will the Kindle be able to handle that, especially if i want to frequently jump pages or refer to multiple books side by side? I have never seen a Kindle in person so anyone who has used it, please comment.
Reading ebooks on my laptop is a pain. I often read through the night and that is not possible for me to do on a laptop. The vertical height is too small and I often end up turning the laptop 90 degree to read. Not to mention, carrying around a laptop in your hand is impossible for long durations. Plus the zoom options on Adobe reader are just weird. In short, I am really uncomfortable reading on a laptop. I have tried both a 14" 1366*768 screen as well as 17" 1920*1080 screen
On the other hand, ipad gives me the advantage of iOS. I will also be able to see OCW videos on the ipad as well as watch my college slides (ppt). Ipad owners please comment-- can i play .avi or real media player file on it directly or through an app? I can also use the educational apps like Khan academy plus it can serve as a note taking device. The disadvantage of the ipad is that reading on it through the night will probably leave me blind in a year or so. I have myopia and my power is -8D. That is one BIG disadvantage, or so I have read. I have never used an ipad so perhaps someone who uses it can share their experience of reading on it for hours at a stretch.
I am really confused about this so I hope the collective intelligence of this site will help me make an informed decision. And I would really like to see a page in the reviews of tablets that talk about the reading and note talking abilities and the educational purposes they can serve.
Monobazus - Thursday, March 29, 2012 - link
I understand your desilusion with the ommission here of any specific discussion of the advantages or desadvantages of using the iPad as a book reader. After all, that may probably be one of the main usages of the iPad, apart from browsing the web or checking the email or Facebook posts. But anandtech.com is mainly a tech site for geeks and technically oriented people, and we must understand that putting a special emphasis on specs and speeds is more interesting for the majority of its readers. For an analysis of your question, you could perhaps go into one of the various sites that deal with ebook readers. Unfortunately most of them, as far as I can tell, have not the level of expertise or care that anantech.com has in its analysis (see http://www.the-ebook-reader.com/ipad-3.html as an example).Now to your questions. I have no direct experience with the new iPad or the kindle DX. I have an iPad 1 and a kindle 3 (the one with the 6" screen and no touch controls). I haven't seen yet the new retina display of the iPad, but from what I've been reading it's much better on text than the previous editions. I doubt however that it is as good for the eyes as the eInk screens are - these are reflective and, as such, closer to paper than LCD screens. From my experience - I'm an intensive reader and use glasses, due to my advanced age - eInk screens don't put as much stress on the eyes as the emissive screens do. If you are planning to read through the night with a LCD screen use an indirect ambient light and plan for frequent periods of rest.
On the other hand, handling pdfs on the Kindle is an awful experience. A DX is certainly better than a 6" one, no doubt, because the bigger screen allows for larger type. On a 6" screen you can forget pdfs. You can't read them. If your typical pdfs can be accommodated in a 9,7" screen without zooming, then a DX can be the eReader for you. But be careful with the illustrations: I think the DX has the same controls that the 6" non-touch kindle. If that's the case be prepared for a bad experience with the illustrations, specially if they are detailed and need zooming (or if they have colour). The DX is a non-touch machine. The iPad touch controls are much better.
You can't see two documents side by side on any of these readers: not on the iPad and not on the Kindle. For that you need a laptop. On the iPad you can use a trick: open one document in one app (say, on the eBook app) and the other in other app (say, on the kindle reader). By switching rapidly between them, you can see the two documents in rapid succession. You can't do that on the Kindle. But this is a trick, a compromise, and not the same thing as looking to two documents side by side.
As to seeing ppt's and videos, the iPad is the way to go. There are apps for that. The kindle has not that capability.
In the end, my advice is this: try to get access to an iPad before buying, and see if it meets your expectations for reading clarity and comfort. Getting access to a DX before buying may be more difficult, because there are few people around with them. I have yet to see one and they are around for several years.
I'm sorry if these considerations haven't been useful for you.
Monobazus - Thursday, March 29, 2012 - link
See this YouTube analysis of the Kindle DX with pdf's: http://www.youtube.com/watch?v=bVPBCD0GgBw&fea...adityarjun - Thursday, March 29, 2012 - link
Thanks you very much for your reply.It does seem as if neither of the two fit my needs perfectly. So I will have to make a compromise.
A 6" kindle or 7" tablet is out the question. It is just too small to read comfortably on.
The Kindle DX's screen and size seemed good to me but if you say that it can't handle pdfs comfortably then it is of no use to me. I will not be viewing any newspapers or magazines nor will I be surfing the net with it.
The only other option that remains is to use the ipad. The pros is that it should be able to handle large pdf *as per videos on youtube* as well as all my videos.
The con is the eye strain.
Is it really as bad as some sites make it out to be? Especially when compared to an e ink reader?
I will try to get my hands on an ipad and use it for a day or two but come to think of it, the screen cant be that much more stressful than a normal laptop, can it? And I have been reading reviews of the SoCs on Anandtech since morning...
Damn, I am really gonna go blind at this rate. *summons immense willpower and tries to close anandtech* * fails :-) *
mr_ripley - Thursday, March 29, 2012 - link
I keep and read all my technical pdf files on the ipad (textbooks, reports, memos, drawings, etc). I use an app called GoodReader which is absolutely amazing with all kinds of pdfs.Regarding eye strain, I usually keep my brightness setting at around 50% and zoom in to make the font large, which strains my eyes a little less and definitely less than a desktop screen. The sharp font on the new retina screen helps as well. That said I will admit it is not as easy on the eyes as an e-ink display.
tbutler - Thursday, March 29, 2012 - link
Honestly? I think the iPad's screen (even the first iPad, let alone the new one) gives me significantly *less* eyestrain than eInk, and I've owned a couple of Sony eInk readers.For me, the key eyestrain issue between the two is contrast. eInk displays are a light grey background with dark grey text, and in bright lighting the contrast is fine. But in less than bright lighting - for example, an indoor room without either a ceiling light fixture or multiple floor lamps - I start having trouble with distinguishing the text. Even a 40-year-old yellowing paperback is easier for me to read under those conditions. While you can use a clip-on reading light, I find that both clunky and less effective than it would be on paper.
The iPad (and really, any backlit LCD screen) has the 'stare into backlight' issue; but honestly, this is rarely a problem for me, and in particular it's much less of a problem than eInk contrast issues. Backlit color LCDs also wash out in bright sunlight, but not in even the most brightly-lit interior room, in my experience - however, for me this isn't a significant issue, since I spend much more time reading indoors than outdoors.
So just in terms of legibility, I'd pick the iPad (or the nook Color/Tablet) over any of the eInk readers I've used. And that's leaving out issues of software and PDF handling.