Apple's iPad - The AnandTech Review
by Anand Lal Shimpi, Brian Klug & Vivek Gowri on April 7, 2010 9:39 PM EST- Posted in
- Smartphones
- Mac
- Apple
- iPad
- Mobile
Honest Apple: Battery Life
I mentioned this in my iPhone 3GS review and I believe it bares repeating: Apple's battery life estimates have been ridiculously accurate over the past couple of years. I swear Apple must have my office bugged because my battery life numbers almost always equal theirs and they have no access to my test files.
To test battery life on the iPad I ran a modified version of the process I use for smartphones. I use the WiFi connection to browse a series of 20 web pages varying in size, spending 20 seconds on each page (I timed how long it takes me to read a page on Digg and came up with 36 seconds; I standardized on 20 seconds for the test to make things a little more stressful). The test continues to loop until the battery dies. This test is designed to simulate a relatively heavy, but realistic data load on the phone. We're stressing the WiFi radio, SoC, memory and display subsystems here. This should also be the sort of battery life you get when you are using any apps that use data (but not 3D acceleration). The display brightness was set to 50% on the iPad.
That's the test I use for smartphones, but to make it a little more stressful on the iPad I continuously played music using the iPod app, one of the only apps that's allowed to run in the background. I also told the mail app to automatically check my AnandTech email account every 15 minutes. I get a good amount of mail so this constant checking would add another realistic component to the workload. I also ran this same test on ASUS Eee PC 1001P:
The iPad came in just shy of Apple's 10 hour claim. At 9 hours and 45 minutes, it's long enough to get you through the greater part of a day. But calling Apple's battery estimates conservative is misleading. A single charge won't last you all day.
The iPad does last longer than ASUS' 1001P, however ASUS tells us that the 1005PE will buy you another 2 hours of battery life for an extra $79.
What about watching movies? Our resident smartphone expert Brian Klug put together a 6 hour loop of The Bourne Ultimatum. This was from a 1080p source but re-encoded using Handbrake's Normal profile resulting in a 1.3GB 720p rip that was looped three times.
I imported the movie into iTunes, synced it to the iPad and looped the already 6 hour loop until the iPad died. Display brightness was set to 50%, auto brightness control was disabled, automatic email downloading was also disabled.
Video playback is actually a fairly light use case. In these SoCs there's usually a dedicated video decode block, most likely the PowerVR VXD (same as in the iPhone 3GS). This block decodes each frame and sends it to the display output engine. The only things working in this case are parts of the CPU, the video decode engine, memory bus and the display engine. There's no 3D rendering and the vast majority of the CPU is idle. With this in mind, it's no surprise that the iPad can last 13.6 hours when playing back a 720p H.264 movie.
| Apple iPhone 3GS | Apple iPad | ASUS Eee PC 1001P | |
| H.264 Video Playback | 9.5 hours | 13.6 hours | 5.3 hours |
The iPhone 3GS however can almost hit 10 hours performing the same test. This gives you an idea of how much power the display is consuming on the iPad. The netbook doesn't stand a chance by comparison. The iPad was made for watching lots of movies on a single battery charge.
My final battery life test was a 3D gaming benchmark. I ran Real Racing HD on the iPad (and Real Racing on the iPhone) until the devices died. The cellular network was turned off on the iPhone 3GS and brightness was set to 50%.
Anything GPU intensive is going to be the worst case scenario for these SoCs. Here we’re stressing the CPU, GPU and memory subsystem. The added load is reflected in the battery life numbers:
| Apple iPhone 3GS | Apple iPad | |
| 3D Gaming | 3.9 hours | 8.8 hours |
The iPhone 3GS approaches 4 hours, while the iPad manages almost 9 hours while gaming. I’d also consider this to be a best case scenario gaming benchmark. A more intense 3D game could easily drop these numbers even further.
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TGressus - Thursday, April 8, 2010 - link
"I don't think anything anyone can write can convince you"That's a tough sell right there :( Nothing against your post.
This is the challenge all tablets have faced so far. That said, if anyone has the ability to succeed in this form factor it's the iCult.
Mike1111 - Thursday, April 8, 2010 - link
"While I realize that Atom hasn't been suited for such an application until now, there's no reason Apple should've picked the A4 over Moorestown. "I really think it was the right decision for Apple to go with ARM for the iPad, and that it's the right decision to stick with ARM for at least the next few years.
(1) Mobile version of Moorestown is not available yet, the netbook one draws too much power
(2) Apple has to use ARM in it's iPhone and iPod touch for the next few years, so for cross-device OS, app and SoC compatibility and development ARM was the right choice for the iPad (e.g. if Apple makes safari use the hardware better on the iPad, the iPhone and iPod touch will directly profit from it too)
(3) Moorestown would have been more expensive
(4) With ARM Apple can control and modify the CPU design as needed, they have total control. And Apple likes that.
(5a) There is a clear upgrade path for ARM with the Cortex-A9 and a multi-core version of it.
(5b) The A4 is already fast enough for most people and most iPad tasks (how many reviews mention that the iPad is unpleasantly slow, even for the average consumer?)
It's a real possibility that an iPad with a more optimized OS and safari, a better utilized (and more programmable) GPU (like the SGX545 with OpenCL etc.) and a dual-core Cortex-A9 @1.x GHz will improve the browsing performance beyond that of a netbook. And IF APPLE SAW THE NEED FOR IT (but I don't think they do), it could happen as early as next year (other ARM SoCs like Tegra2, OMAP4 and the dual-core Snapdragon will be available by then with comparable specs, so Apple should be able to pull it off too). Intel's Atom will still be a more power consuming, more expensive and way bigger multi-chip system early next year. And beyond that are ARM quad-core CPUs and dual-core GPUs...
It will take Atom at least 4 years to overtake ARM, in the areas that count for dedicated smartphones/slates/tablets, if at all. At some point, real life browsing will just be fast enough on an ARM slate and Intel netbook, so that 99% don't care about browsing speed as a feature anymore (like it will happen with video thanks to all these powerful but small dedicated decoders/encoders like IMG's VXD/VXE).
softdrinkviking - Thursday, April 8, 2010 - link
are you saying that there is no clear upgrade path for intel's moorstown line?and that apple has complete control over the future of ARM?
i didn't know they had already gone that far.
i seem to remember apple fumbling out of the power series of CPUs and crawling into into intel's arms when they realized it was the way to go.
there is nothing to prevent apple from switching to moorstown in a couple of generations, and they have proven that they are willing to make those kind of changes when the situation demands it.
Mike1111 - Friday, April 9, 2010 - link
"are you saying that there is no clear upgrade path for intel's moorstown line?"Of course not. I'm just saying that even if you think the ARM Cortex-A8 used in the iPad is not powerful enough, that there are clear CPU upgrades coming your way for years to come (higher frequencies, Cortex-A9, dual-core Cortex-A9, quad-core Cortex-A9). It's not like Apple is using a quad-core Cortex-A9 @ 4 GHz in 22nm right now, with no better ARM architecture on the horizon and standard lithography reaching a dead end...
"and that apple has complete control over the future of ARM? i didn't know they had already gone that far."
Sorry, what I meant was that Apple has complete control over how they implement the ARMv7 architecture in a chip (since Apple has most likely an architecture license like Qualcomm).
"there is nothing to prevent apple from switching to moorstown in a couple of generations, and they have proven that they are willing to make those kind of changes when the situation demands it."
I agree that Apple can and most likely will switch to Intel if their chips are clearly superior in all the ways that matter for a mobile product. I just think that's at least 4-5 years out for retail devices so there's no point in talking about how Apple should have used Moorestown for this year's iPad... or any iPad for that matter. I don't even think that Moorestown's successor will be ready (Medfield). Maybe Medfield's successor's successor in 22nm will be clearly superior (although parity could be reached a generation earlier). We'll see.
MadAd - Thursday, April 8, 2010 - link
Its huge. Way too big for car centre consoles. If they cut it in half, so its mid way between that and an Iphone then I would definitely want to upgrade my existing car PC.Its got all the right airs and graces to be a super satnav/speedcam/music/incar wifi unit, just need to cut the size and sell it with some kind of some kind of quick release device for power and cabling (or ill fabricate one) and its a winner.
teng029 - Thursday, April 8, 2010 - link
"Companies like Crestron and AMX supply ridiculously poor touch screen interfaces to their very expensive home automation installations."How exactly did you come to this conclusion? Have you extensively either used or program a control system touch panel?
Anand Lal Shimpi - Thursday, April 8, 2010 - link
Used, but not programmed. Those touchscreen controllers are just not in the same league in terms of UI as the iPad/iPhone honestly. I haven't used the latest incarnations but from the looks of them, they haven't changed tremendously.Take care,
Anand
athreya - Thursday, April 8, 2010 - link
1. Does writepad (phatware) or sketchbook pro (autodesk) allow one to take handwritten notes on the ipad? As in, im not looking for handwriting conversion to pages or word but can notes be taken and emailed across in the body of say a gmail or a Mail message? WHich stylus is the best for the ipad?2. How do you think iphone os 4.0 will solve the multitasking problem?
3. Between the wireless keyboard and the keyboard with dock which would you recommend and why? Will ANY BT keyboard work with the ipad?
4. Can you tell us how good it is at projecting powerpoint ppts onto a standard VGA projector? Does it support Office for Mac yet?
thanks a lot Anand. Terrific balanced review as always.
strikeback03 - Friday, April 9, 2010 - link
I doubt any stylus works with the iPad, due to the capacitive screen.dagamer34 - Friday, April 9, 2010 - link
A capacitive stylus would work.