Apple's iPhone 4: Thoroughly Reviewed
by Brian Klug & Anand Lal Shimpi on June 30, 2010 4:06 AM EST- Posted in
- Smartphones
- Apple
- iPhone 4
- Gadgets
- Mobile
Incredible Battery Life
I’ve publicly praised Apple for its honesty in reporting battery life over the past couple of years, and the iPhone 4 gives me no reason to stop.
The 4 has an integrated 5.25Whr battery. That’s around 95% of the battery capacity of the HTC EVO 4G, despite having much lower power frequirements. It’s also a 16% increase over the 4.51Whr battery that was in the iPhone 3GS. This means at bare minimum, assuming the iPhone 4 doesn’t draw any more power than the 3GS, we should get 16% more battery life.
In reality, we get much more.
When Apple introduced the iPhone 3G it dropped battery life to a level that we’d been stuck at ever since. The 3GS improved battery life a bit through better CPU power efficiency but you still didn’t have enough juice to get through a day without charging.
The iPhone 4 changes all of that. The combination of a larger battery and a more power efficient SoC results in an incredible amount of battery life.
Our first test is a basic web browsing benchmark. We've scripted almost two dozen webpages to load, pause for 20 seconds, then forward on to the next page. None of the pages use any Flash. This process repeats until the battery is dead. Screen brightness on the iPhones was set to 50% and the screens remained on the whole time.
Battery life improved nearly 38% with the iPhone 4. It's clear that while the A4 improved performance, the real improvement was in battery life. This test has enough idle time where good power management and low idle power can really impact the results. There's simply no other similar smartphone that can touch the 4's battery life.
We then repeated the same test over WiFi instead of 3G:
Apple claims the iPhone 4 will last for up to 10 hours over WiFi, we measured just under that at 9.96 hours. The improvement here is only 12.8%, which tells me that we're nearing the limit of how efficiently Apple can manage power in WiFi mode. There's a wall that we're quickly approaching with this current architecture.
To measure talk time we play MP3s on repeat into the mic of a phone and use it to call the phone being tested. The process continues until the test phone dies. In this case the screen is allowed to go to sleep, as it normally would be if you were talking on the phone:
Apple promised up to 7 hours of 3G talk time with the iPhone 4. We measured 7.47 hours. That's an increase of 54.9% over the iPhone 3GS. While in a phone call the majority of the A4 SoC is powered down, so the efficiency improvements here have to do with how much less power the A4 consumes while off and the new Skyworks 3G modem (the iPhone 3GS used an Infineon modem).
In our iOS 4 review we looked at the impact multitasking had on the iPhone 3GS' web browsing battery life. I ran our 3G web browsing test while playing music through Pandora in the background. I repeated the test with the iPhone 4 for today's article:
We actually see our largest battery life improvement in this test. With a 57.7% increase in battery life over the 3GS, the iPhone 4 is not only more efficient at idle workloads but also when the SoC is constantly busy. The A4 SoC is rumored to be built on a 45nm process compared to the 65nm SoC used in the 3GS. With a moderate increase in clock speed we should be seeing a lot of the power savings that a full node shrink brings to the table.
The battery life offered by the iPhone 4 is spectacular. My iPhone 3GS could hardly get through a full day of work while traveling, I'd always need to hunt for an outlet before heading into my dinner meeting. I'm about to take my first trip with the iPhone 4 but I get the feeling that I might finally be able to make it through dinner.
Early reports of 20 and 30 hours of battery life are simply exaggerated. They're only possible if you let the phone idle in your pocket for the majority of that time. In other words, if you don't use the phone it lasts for a long time. While that's a testament to the platform's incredible idle power, the real world usage is good enough to stand on its own. It's better than any iPhone or Android phone I've tested thus far.
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metalev - Saturday, July 3, 2010 - link
I ploted the signal-strength-to-bars mapping for both Android and the iPhone 4 on the same axes:http://www.metalev.org/2010/07/android-vs-iphone-4...
This shows that the iPhone 4 consistently reports a higher percentage signal strength (as defined by the fraction of bars lit) than Android GSM devices at the same signal strength.
R. Johnson - Saturday, July 3, 2010 - link
I don't understand how Apple (Iphone4) can say the antenna issue is a math problem when I can sit here with all full antenna bars and then hold the phone with my left hand and get only half a bar within 15 seconds. I don't know what to trust anymore when Apple decides to use different math and different bars in an upcoming update. I am afraid they may now use different bars to have it APPEAR there is better reception than there really is.R. Johnson
SunSamurai - Saturday, July 3, 2010 - link
You better hurry and put on the tinfoil hat too.Give me a break. The article already pointed out it was a simple error in how the bars were representing signal. The actual numerical signal is actually better. They basically did the opposite of what youre freak'n out about.
navderek - Saturday, July 3, 2010 - link
@SunSamuraiPlenty of reason to freak out. This is a very obvious design flaw that has been overlooked by Apple, and now denied by Apple. I am an RF Engineer and when I watched the Apple keynote presentation of the device I almost fell off my chair when he presented the antenna design...Then I thought, no it must have a light coat of something to shield the antenna....guess not.
Apple is making profit hand over fist and paying sweatshop workers pennies to put these things together...the least they could do is provide free bumpers. No they won't though because they will open the door to legal issues...who cares, they can afford the legal costs and it would save their face and allow them to continue unscathed...Now they just look like any other greedy company out there. They've really lost there magic IMO. It's discouraging that profits > honor. They are a real good company and this will really hurt them.
StormyParis - Saturday, July 3, 2010 - link
The article is very nice, but the conclusion lets us down and not gently by falling into the fanboi worldview. I'm neither an Apple nor Android nor Palm fanboi. I recently bought an HD2, and I'm definitely NOT an MS fanboi. I just wanted the biggest possible screen, and the HD2's is 40% bigger than the iPhone's... it's not about resolution, but size: I'm getting old.If the Dell Streak had been out in my country, I'd probably have gotten it instead. If palm had a big-screen, keyboardless phone, I'd have strongly considered it, seeing that right before the HD2, I was still using my Palm TX because it just works.
Right now I wouldn't consider Apple because it's too closed, and too cumbersome to get content onto (iTunes crapped out on my PC every time I tried it). I'm not sure I could get winhttrack'ed sites onto it.
I think most phones have reached the point of "good enough". On mine, I'm using a browser, an ebook reader, a media player... and that's about it. I don't game, I don't do social web things, I don't need a fashion accessory/personality crutch...
SunSamurai - Saturday, July 3, 2010 - link
You sound bitter. Tell us where the iphone/droid touched you.btharms - Saturday, July 3, 2010 - link
My phone drops from 5 bars to 1 bar frequently. The way I comfortably hold the phone covers the black strip more often than not. I have run speed test after speed test, and what I have found is that while covering the strip, my 3g connection will drop to 0kbps! I can literaaly freeze safari while loading any web page by temporarily placing my finger on the black strip (it will continue to load a second or two after I remove my finger).I was achieving download speeds of around 1600 kilobits/sec with the phone in my hand without covering the black strip. When redoing the test while holding the phone normally (with my pinky finger covering the strip) the speed dropped as low as 0 (100 kilobits per second was the fastest). Actually, many times the test would not start until I removed my pinky from the spot. Then, after the test began I would softly place my pinky back on the strip - and instantly the speed drops near 0.
So as thorough as your testing was, realizing that the phone misrepresents signal strength is really not a pertinent issue when you consider that the 3g signal virtually dissapears immediately on contact with the black strip.
I'm basically demanding that apple comps me a free bumper or i'm returning my phone.
navderek - Saturday, July 3, 2010 - link
The main point is that by Apple redoing the math on the signal bars...it will have no effect on the issues your seeing. Bars don't man a thing. Real life means everything and if the call drops with 5 bars or zero bars it does not matter - the call still drops!THIS IS JUST A STUNT BY APPLE TO PUT THE BLAME ON THE CARRIERS...OPEN YOUR EYES PEOPLE. Once the SW update happens then people will go back to complaining about AT&T and others...just like Apple wants it.
Thing is, poeple aren't as dumb as Apple thinks. But I guess this is the most financially obvious thing for Apple to do. Shift the blame, it's not our problem!
Mike Wadner - Saturday, July 3, 2010 - link
I started reading your review and stopped immediately upon seeing this statement: Apple has real competitors in the smartphone space. Android phones have grown in features, polish and popularity. Even Palm entered the race with a competant offering, and Microsoft isn't far behind.What cave have you been in for the last year? Do you not have a F**KING clue what Microsoft just did with their phone this week - THEY ARE MILES BEHIND EVERYONE IN HARDWARE AND SOFTWARE. My 13 year old kid wouldn't even make a statement this stupid.
Microsoft is stillborn when it comes to mobile. To even consider Microsoft a worthy competitor in the smart phone area is insane.
You're credibility just went down the crapper with that statement.
navderek - Saturday, July 3, 2010 - link
Agreed...the review may be good to the laymen, but for others not so much. I highly respect Anandtech's reviews but this is really the first one I've seen where they seem to have done the review just to get some of that Apple limelight without actually asking the tough questions like why Apple went and designed the antenna like this? What is the link between this poor antenna design and the sudden sale of bumpers by Apple? hmmmmmm