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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softdrinkviking - Thursday, April 8, 2010 - link
it occurs to me that i would want a way to protect the screen from getting scratched, and that would mean acover or case that would take the place of the clamshell design of a netbook/notebook.
why would i want to pay a price premium for a device with slower performance which only achieves acceptable functionality with the addition of expensive peripherals?
even after all the peripherals, i still lose the ability to effortlessly prop-up a netbook on my lap and type an email, or set a netbook up on a table in a coffee shop.
nothing about the tablet form factor is convenient for on-the-go usage for me.
the only situation where i can possibly imagine this being a preferable form factor is for wall mount usage or some other kind of "always left out in the open" type of use, like a universal remote control, or a mini home television viewer in the kitchen.
but it seems too expensive for those uses to me.
there must be a better alternative.
MacTheSpoon - Thursday, April 8, 2010 - link
Thanks for the great review. I was shocked you'd typed 40% of it with the iPad.Would you mind doing a comparison between the iPad keyboard and a physical keyboard? Since there is no utility to measure WPM for the iPad, maybe you could time how long it takes to type the same passage on both--something with some semicolons, quotation marks, and/or em dashes would be ideal, as I'm curious how the virtual keyboard stands up when the user must switch between layouts.
Brian Klug - Thursday, April 8, 2010 - link
You know, this was something I was dying to address a few times. I'm hoping that the iTextspeed application developers update their code soon to be iPad compatible, because that's something I want to test for sure.I've gotten to the point where I can touch type in landscape pretty easy, but I can also type pretty fast on the iPhone (around 80 WPM using their application). If and when it's updated, we might do something and include the update.
If it helps any, this was also composed pretty quickly from an iPad. ;)
Cheers,
Brian Klug
solipsism - Thursday, April 8, 2010 - link
1) How did you get a 720p video on the iPhone for the video test when the allowable maximum "up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second" video?2) From my testing, the iPad uses about 20MB more than the 3GS on startup. Most, if not all, of this is for the GPU. I've also noticed that native apps are also using more RAM. While the 3GS has enough to support standard multitasking the iPad does not. Even switching pages in Safari on the iPad would have to be reloaded while the 3GS does not. This will even more of an issue with the 3G version of the iPad. This gives me doubts about multitasking unles iPhone OS v4.0 is much more efficient (making 3.2.2 a stand in, which looks to be the case) and Apple has a more intuitive quasi-multitasking concept to unveil today.
Brian Klug - Thursday, April 8, 2010 - link
I can't speak about the RAM usage - are you using iStat or similar?However 720P H.264 video is certainly supported, which is what we used. I tested all the different profiles in handbrake, all of them work if you keep the video at or under 1280x720:
"H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format"
That's straight from http://www.apple.com/ipad/specs/
I think you're getting confused with the MPEG4 limitation which is indeed 640x480. ;)
-Brian Klug
Ph00 - Thursday, April 8, 2010 - link
sorry to be ot but is that a black mouth cur dog?Griswold - Thursday, April 8, 2010 - link
I'll wait for iPad v2 with reliably working wifi, no overheating, working PDF export, at least a backside camera for snapshots and maybe short flicks and perhaps multitasking. Ill stop here because any more missing features would seem greedy - apple needs a reason to sell you the 2012 iPad...As for atom based ipad - are you nuts? Nobody wants that garbage. Gimme a dual core cortex A9 instead.
Mike1111 - Thursday, April 8, 2010 - link
You mean the 2011 iPad, right? Because there's no way Apple isn't gonna do a yearly refresh cycle like they do with all their iPhone OS based products.Mike1111 - Thursday, April 8, 2010 - link
My mistake. You meant even iPad v2 in 2011 won't be feature complete because Apple needs some features for the 2012 iPad v3.Hm, how do I delete a post?
Lemonjellow - Thursday, April 8, 2010 - link
"Sure, but so could a TV that made me pancakes. Neither is ready yet or guaranteed."Can you confirm or deny that someone is working on said TV project? :- D