The Apple iPad Review (2012)
by Vivek Gowri & Anand Lal Shimpi on March 28, 2012 3:14 PM ESTThe A5X SoC
The ridiculousness of the new iPad begins at its heart: the A5X SoC.
The A5X breaks Apple's longstanding tradition of debuting its next smartphone SoC in the iPad first. I say this with such certainty because the A5X is an absolute beast of an SoC. As it's implemented in the new iPad, the A5X under load consumes more power than an entire iPhone 4S.
In many ways in the A5X is a very conservative design, while in others it's absolutely pushing the limits of what had been previously done in a tablet. Similar to the A5 and A4 before it, the A5X is still built on Samsung's 45nm LP process. Speculation about a shift to 32nm or even a move TSMC was rampant this go around. I'll admit I even expected to see a move to 32nm for this chip, but Apple decided that 45nm was the way to go.
Why choose 45nm over smaller, cooler running options that are on the table today? Process maturity could be one reason. Samsung has yet to ship even its own SoC at 32nm, much less one for Apple. It's quite possible that Samsung's 32nm LP simply wasn't ready/mature enough for the sort of volumes Apple needed for an early 2012 iPad launch. The fact that there was no perceivable slip in the launch timeframe of the new iPad (roughly 12 months after its predecessor) does say something about how early 32nm readiness was communicated to Apple. Although speculation is quite rampant about Apple being upset enough with Samsung to want to leave for TSMC, the relationship on the foundry side appears to be good from a product delivery standpoint.
Another option would be that 32nm was ready but Apple simply opted against using it. Companies arrive at different conclusions as to how aggressive they need to be on the process technology side. For example, ATI/AMD was typically more aggressive on adopting new process technologies while NVIDIA preferred to make the transition once all of the kinks were worked out. It could be that Apple is taking a similar approach. Wafer costs generally go up at the start of a new process node, combine that with lower yields and strict design rules and it's not a guarantee that you'd actually save any money from moving to a new process technology—at least not easily or initially. The associated risk of something going wrong might have been one that Apple wasn't willing to accept.
| CPU Specification Comparison | ||||||||
| CPU | Manufacturing Process | Cores | Transistor Count | Die Size | ||||
| Apple A5X | 45nm | 2 | ? | 163mm2 | ||||
| Apple A5 | 45nm | 2 | ? | 122mm2 | ||||
| Intel Sandy Bridge 4C | 32nm | 4 | 995M | 216mm2 | ||||
| Intel Sandy Bridge 2C (GT1) | 32nm | 2 | 504M | 131mm2 | ||||
| Intel Sandy Bridge 2C (GT2) | 32nm | 2 | 624M | 149mm2 | ||||
| NVIDIA Tegra 3 | 40nm | 4+1 | ? | ~80mm2 | ||||
| NVIDIA Tegra 2 | 40nm | 2 | ? | 49mm2 | ||||
Whatever the reasoning, the outcome is significant: the A5X is approximately 2x the size of NVIDIA's Tegra 3, and even larger than a dual-core Sandy Bridge desktop CPU. Its floorplan is below:
Courtesy: Chipworks
From the perspective of the CPU, not much has changed with the A5X. Apple continues to use a pair of ARM Cortex A9 cores running at up to 1.0GHz, each with MPE/NEON support and a shared 1MB L2 cache. While it's technically possible for Apple to have ramped up CPU clocks in pursuit of higher performance (A9 designs have scaled up to 1.6GHz on 4x-nm processes), Apple has traditionally been very conservative on CPU clock frequency. Higher clocks require higher voltages (especially on the same process node), which result in an exponential increase in power consumption.
| ARM Cortex A9 Based SoC Comparison | ||||||
| Apple A5X | Apple A5 | TI OMAP 4 | NVIDIA Tegra 3 | |||
| Manufacturing Process | 45nm LP | 45nm LP | 45nm LP | 40nm LPG | ||
| Clock Speed | Up to 1GHz | Up to 1GHz | Up to 1GHz | Up to 1.5GHz | ||
| Core Count | 2 | 2 | 2 | 4+1 | ||
| L1 Cache Size | 32KB/32KB | 32KB/32KB | 32KB/32KB | 32KB/32KB | ||
| L2 Cache Size | 1MB | 1MB | 1MB | 1MB | ||
| Memory Interface to the CPU | Dual Channel LP-DDR2 | Dual Channel LP-DDR2 | Dual Channel LP-DDR2 | Single Channel LP-DDR2 | ||
| NEON Support | Yes | Yes | Yes | Yes | ||
With no change on the CPU side, CPU performance remains identical to the iPad 2. This means everything from web page loading to non-gaming app interactions are no faster than they were last year:
JavaScript performance remains unchanged, as you can see from both the BrowserMark and SunSpider results above. Despite the CPU clock disadvantage compared to the Tegra 3, Apple does have the advantage of an extremely efficient and optimized software stack in iOS. Safari just went through an update in improving its Javascript engine, which is why we see competitive performance here.
Geekbench has been updated with Android support, so we're able to do some cross platform comparisons here. Geekbench is a suite composed of completely synthetic, low-level tests—many of which can execute entirely out of the CPU's L1/L2 caches.
| Geekbench 2 | ||||||
| Apple iPad (3rd gen) | ASUS TF Prime | Apple iPad 2 | Motorola Xyboard 10.1 | |||
| Integer Score | 688 | 1231 | 684 | 883 | ||
| Blowfish ST | 13.2 MB/s | 23.3 MB/s | 13.2 MB/s | 17.6 MB/s | ||
| Blowfish MT | 26.3 MB/s | 60.4 MB/s | 26.0 MB/s | - | ||
| Text Compress ST | 1.52 MB/s | 1.58 MB/s | 1.51 MB/s | 1.63 MB/s | ||
| Text Compress MT | 2.85 MB/s | 3.30 MB/s | 2.83 MB/s | 2.93 MB/s | ||
| Text Decompress ST | 2.08 MB/s | 2.00 MB/s | 2.09 MB/s | 2.11MB/s | ||
| Text Decompress MT | 3.20 MB/s | 3.09 MB/s | 3.27 MB/s | 2.78 MB/s | ||
| Image Compress ST | 4.09 Mpixels/s | 5.56 Mpixels/s | 4.08 Mpixels/s | 5.42 Mpixels/s | ||
| Image Compress MT | 8.12 Mpixels/s | 21.4 Mpixels/s | 7.98 Mpixels/s | 10.5 Mpixels/s | ||
| Image Decompress ST | 6.70 Mpixels/s | 9.37 Mpixels/s | 6.67 Mpixels/s | 9.18 Mpixels/s | ||
| Image Decompress MT | 13.2 Mpixels/s | 20.3 Mpixels/s | 13.0 Mpixels/s | 17.9 Mpixels/s | ||
| Lua ST | 257.2 Knodes/s | 417.9 Knodes/s | 257.0 Knodes/s | 406.9 Knodes/s | ||
| Lua MT | 512.3 Knodes/s | 1500 Knodes/s | 505.6 Knodes/s | 810.0 Knodes/s | ||
| FP Score | 920 | 2223 | 915 | 1514 | ||
| Mandelbrot ST | 279.5 MFLOPS | 334.8 MFLOPS | 279.0 MFLOPS | 328.9 MFLOPS | ||
| Mandelbrot MT | 557.0 MFLOPS | 1290 MFLOPS | 550.3 MFLOPS | 648.0 MFLOPS | ||
| Dot Product ST | 221.9 MFLOPS | 477.5 MFLOPS | 221.5 MFLOPS | 455.2 MFLOPS | ||
| Dot Product MT | 438.9 MFLOPS | 1850 MFLOPS | 439.4 MFLOPS | 907.4 MFLOPS | ||
| LU Decomposition ST | 217.5 MFLOPS | 171.4 MFLOPS | 214.6 MFLOPS | 177.9 MFLOPS | ||
| LU Decomposition MT | 434.2 MFLOPS | 333.9 MFLOPS | 437.4 MFLOPS | 354.1 MFLOPS | ||
| Primality ST | 177.3 MFLOPS | 175.6 MFLOPS | 178.0 MFLOPS | 172.9 MFLOPS | ||
| Primality MT | 321.5 MFLOPS | 273.2 MFLOPS | 316.9 MFLOPS | 220.7 MFLOPS | ||
| Sharpen Image ST | 1.68 Mpixels/s | 3.87 Mpixels/s | 1.68 Mpixels/s | 3.86 Mpixels/s | ||
| Sharpen Image MT | 3.35 Mpixels/s | 9.85 Mpixels/s | 3.32 Mpixels/s | 7.52 Mpixels/s | ||
| Blur Image ST | 666.0 Kpixels/s | 1.62 Kpixels/s | 664.8 Kpixels/s | 1.58 Kpixels/s | ||
| Blur Image MT | 1.32 Mpixels/s | 6.25 Mpixels/s | 1.31 Mpixels/s | 3.06 Mpixels/s | ||
| Memory Score | 821 | 1079 | 829 | 1122 | ||
| Read Sequential ST | 312.0 MB/s | 249.0 MB/s | 347.1 MB/s | 364.1 MB/s | ||
| Write Sequential ST | 988.6 MB/s | 1.33 GB/s | 989.6 MB/s | 1.32 GB/s | ||
| Stdlib Allocate ST | 1.95 Mallocs/sec | 2.25 Mallocs/sec | 1.95 Mallocs/sec | 2.2 Mallocs/sec | ||
| Stdlib Write | 2.90 GB/s | 1.82 GB/s | 2.90 GB/s | 1.97 GB/s | ||
| Stdlib Copy | 554.6 MB/s | 1.82 GB/s | 564.5 MB/s | 1.91 GB/s | ||
| Stream Score | 331 | 288 | 335 | 318 | ||
| Stream Copy | 456.4 MB/s | 386.1 MB/s | 466.6 MB/s | 504 MB/s | ||
| Stream Scale | 380.2 MB/s | 351.9 MB/s | 371.1 MB/s | 478.5 MB/s | ||
| Stream Add | 608.8 MB/s | 446.8 MB/s | 654.0 MB/s | 420.1 MB/s | ||
| Stream Triad | 457.7 MB/s | 463.7 MB/s | 437.1 MB/s | 402.8 MB/s | ||
Almost entirely across the board NVIDIA delivers better CPU performance, either as a result of having more cores, having higher clocked cores or due to an inherent low-level Android advantage. Prioritizing GPU performance over a CPU upgrade is nothing new for Apple, and in the case of the A5X Apple could really only have one or the other—the new iPad gets hot enough and draws enough power as it is; Apple didn't need an even more power hungry set of CPU cores to make matters worse.
Despite the stagnation on the CPU side, most users would be hard pressed to call the iPad slow. Apple does a great job of prioritizing responsiveness of the UI thread, and all the entire iOS UI is GPU accelerated, resulting in a very smooth overall experience. There's definitely a need for faster CPUs to enable some more interesting applications and usage models. I suspect Apple will fulfill that need with the A6 in the 4th generation iPad next year. That being said, in most applications I don't believe the iPad feels slow today.
I mention most applications because there are some iOS apps that are already pushing the limits of what's possible today.
iPhoto: A Case Study in Why More CPU Performance is Important
In our section on iPhoto we mentioned just how frustratingly slow the app can be when attempting to use many of its editing tools. In profiling the app it becomes abundantly clear why it's slow. Despite iPhoto being largely visual, it's extremely CPU bound. For whatever reason, simply having iPhoto open is enough to eat up an entire CPU core.
Use virtually any of the editing tools and you'll see 50—95% utilization of the remaining, unused core. The screenshot below is what I saw during use of the saturation brush:
The problem is not only are the two A9s not fast enough to deal with the needs of iPhoto, but anything that needs to get done in the background while you're using iPhoto is going to suffer as well. This is most obvious when you look at how long it takes for UI elements within iPhoto to respond when you're editing. It's very rare that we see an application behave like this on iOS, even Infinity Blade only uses a single core most of the time, but iPhoto is a real exception.
I have to admit, I owe NVIDIA an apology here. While I still believe that quad-cores are mostly unnecessary for current smartphone/tablet workloads, iPhoto is a very tangible example of where Apple could have benefitted from having four CPU cores on A5X. Even an increase in CPU frequency would have helped. In this case, Apple had much bigger fish to fry: figuring out how to drive all 3.1M pixels on the Retina Display.
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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.