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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solipsism - Thursday, April 8, 2010 - link
I also thought the Moorestown recommendation was odd, especially when the next page was about the phenomenal battery life. If he made a more detailed case for it perhaps he'd have a point, but the simple "because it's faster" stance is lacking.Anand Lal Shimpi - Thursday, April 8, 2010 - link
Initial power specs for Moorestown appear to be fairly competitive with ARM based SoCs. Remember this is Moorestown, and not Pineview. The two chips are very different.Realistically I don't think it would be Moorestown, but the 32nm follow-on starts to make a lot of sense.
Take care,
Anand
metafor - Thursday, April 8, 2010 - link
Just curious, what are the initial power numbers for Moorestown anyway? Keep in mind that with the change in bus architecture and the use of LP DRAM, performance will be significantly slower in some cases than current netbooks. Also, would it really compare to an A9-class SoC?IntelUser2000 - Friday, April 9, 2010 - link
I have a feeling Apple didn't go Moorestown for two primary reasons.1) Timeframe
2) Cost
Moorestown should be announced shortly, but the devices based on it won't be available until Q3 of this year. That's 6+ months from when the iPad is going to release. And although Intel might achieve both better performance and comparable power usage, but the sacrifice there will be higher cost. Fully integrated SoC like the A4 costs significantly less.
Performance should be quite good. There's a 600MHz version for smartphones that can use Burst Mode to 1.2GHz, and a MID oriented version that probably clocks at 1.3GHz base and does 1.9GHz burst. It's supposed to feature "Bus Turbo" as well.
If they also do a full integrated memory controller unlike Pineview we have a good chance it'll be clock per clock faster than Netbook Atoms. Earlier on Intel claimed "30%" boost over previous platform but clock speeds weren't mentioned.
metafor - Friday, April 9, 2010 - link
Moorestown will be a fully interated SoC. It'll have LP DDR1 and LP DDR2 memory controllers as well as a GPU, the Atom CPU and various peripheral connectivity. It's comparable to the A4 in terms of features although I really would not write it off as "comparable" in terms of power until some data is published.ekul - Thursday, April 8, 2010 - link
I'd agree the successor to moorestown is more promising. Are there even any shipping products based on moorestown yet? I don't think apple is going to take a gamble on an untested platform.I'm genuinely looking forward to seeing performance numbers for cortex a9, especially since there will be real dual core mobile variants, not just hyperthreading. A technique like what MS is planning for IE9, rendering a website on one core and compiling javascript on another, would help bridge the perormance gap along with the higher clocks.
michal1980 - Wednesday, April 7, 2010 - link
really this is easier then a laptop/notebook?A notebook by its vary nature I can rest on my lap or a table and adjust its screen. To watch a movie I dont have to hold the thing up.
To type, I dont have to bend to werid angles to hold the device up, etc etc.
IMHO, it seems like alot of the experance is attributed to the newness of the device vs its actual usage. I'm wonder how this newness will wear.
manicfreak - Thursday, April 8, 2010 - link
Can't you do all of those aforementioned things on an ipod touch/iphone? There are already home automation apps for the iphone right now.What can the iPad do that the iphone/ipod touch can't? Beside having a bigger screen and longer battery life?
And for such a big device, the performance should be closer to an atom instead of a snapdragon.
If something doesn't fit in my pocket, then I would rather bring a light-weight CULV laptop with me... with touchscreen if one wishes (i.e. Acer Timeline 1820T) or a hybrid notebook-tablet (Lenovo IdeaPad U1).
jasperjones - Thursday, April 8, 2010 - link
"there are some things the iPad does much better than anything you might own today. Web browsing, photo viewing, reading email, any passive usage scenarios where you're primarily clicking on things and getting feedback, the iPad excels at."What exactly makes it better at those tasks? It's not that I disagree but, in my opinion, you didn't drive this point home. I don't understand why you think it's better. And yes, I read the whole article.
solipsism - Thursday, April 8, 2010 - link
I don't think anything anyone can write can convince you. Many aspects just feel more natural to use. That isn't to say it's perfect everywhere but I think that as a casual mobile consumption device it's much better than a notebook, and much better than a netbook.