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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Griswold - Wednesday, June 30, 2010 - link
Lets be honest, he has only very limited means to meassure the problem. To get to the bottom of this, it needs to be meassured in a HF lab.samspqr - Wednesday, June 30, 2010 - link
"The fact that Apple didn't have the foresight to coat the stainless steel antenna band with even a fraction of an ounce worth of non-conductive material either tells us that Apple doesn't care or that it simply doesn't test thoroughly enough."I find it really funny that they would never catch this specific problem because of them just being apple: if their engineers are not as good as anand is (as in thinking "that's gonna be a problem" right after hearing the description of the antenna), and if THE FIELD TESTERS HAD THEIR PHONES DRESSED AS A 3GS BECAUSE OF PARANOID ISSUES, this kind of problem can only slip through
The0ne - Wednesday, June 30, 2010 - link
I think Anand was a little light on this topic. As an multi-discipline engineer myself this type of problem with the Antenna SHOULD NEVER had happened. It can only happened due to decisions that did not properly address it. This is not rocket science to engineers. If anything, testing WOULD HAVE discover the problem and yet it's in the finish product. Quite sad if you ask me.For example, why put a ferrite clamp on the end of the cable instead of designing it into the PCB . The only reason I can see why we did this was due to lack of time and we severely paid for it by having products become defective because the ferrite would pull the cables loose from the connectors.
deppbv78 - Wednesday, June 30, 2010 - link
I'm really disappointed at the lengths taken by AT to justify that iP4 losing signal as not a big deal...If it was any other product from any other manufacturer, I'm sure you'd not have gone to such lengths to justify the signal drop and just concluded that the phone has serious antenna problems. I'm not understanding why is it so difficult for anyone just provide an unbiased view of the product.I have HTC Hero & Touch Pro both of which lost a bar or two (with fluctuations) when cupped tightly. However, it was always just 1-2 bars and never went down like iPhone 4 does from 5 bars to 0. This continuous loss of signal is the problem. Justifying it telling that all phones lose signal is not right, as every other phone (including 3GS) loses signal temporarily and then stabilizes unlike iPhone 4.
No wonder the iPhone 4 is engineering marvel, but that set aside it is also true that the design has created issues as well and the reviews need to acknowledge it and not justify it
geniekid - Wednesday, June 30, 2010 - link
HTC Incredible owner here. I think AT successfully showed that the antenna issue is NOT a big deal and their methods for doing so are sound. I share your suspicion that maybe they wouldn't have made such a significant investigation if it had been another phone, but let's not accuse them of mistakes they haven't made yet.bplewis24 - Wednesday, June 30, 2010 - link
I have a sincere question though. Does this test really successfully show the antenna issue is NOT a big deal, or does it simply show that it's not a big deal in the utmost ideal conditions?Sometimes the article is difficult to decipher in terms of understanding who is saying what, but upon my initial reading I take it Brian did the testing of the antenna in Arizona. By his own admission (from my understanding), he lives there because the reception is absolutely stellar and about as good as it can possibly be.
Again, from what I can tell, it is under those conditions that he conducted the attenuation signal loss comparisons. If it still drops down to 1 bar and comes reasonably close to dropping calls under the best possible conditions, how does it react under "average" conditions? Other people are reporting dropped calls for a reason. Is Brian's test the norm or an outlier?
Please correct me if I've read this article wrong.
Brandon
anactoraaron - Wednesday, June 30, 2010 - link
My understanding is you are partially correct in assuming (which is what I interpreted from your post) that under "normal" or "average" conditions you will go to one bar - which with the improved reception even at 1 bar you are still fine - OR will drop signal completely.This is also the reason why they say "At the bare minimum Apple should give away its bumper case with every iPhone 4 sold."
Again, fantastic in-depth review.
strikeback03 - Thursday, July 1, 2010 - link
Well, he said the location he lives in has stellar reception. But he also said he drove around for a day testing, which implies to me that he found somewhere with a stable, "average" signal and did some testing there, then probably went somewhere with a "poor" signal and did some more, etc.bplewis24 - Friday, July 2, 2010 - link
@strikeback03Correct. And in driving around to the less-than-stellar areas showed the phone dropping down below -107dB for reception when showing less than 2 bars. And this is on the low end of the reception spectrum as described earlier in the article. So it's pretty clear that the antenna does INDEED show poor signal strength in average or less than average areas when the "death grip" is applied.
That is the determining factor. That determines that the design is defective and flawed. If it was not designed that way, when in average or below signal areas, the reception would still be average or below, and not well below because of the way you hold the phone.
However, the article skirts this and attempts to present it in a way that shines the best possible light on Apple and their defective design. Big disappointment in terms of an objective review.
Brandon
geniekid - Wednesday, June 30, 2010 - link
The article made it clear that bars are a misleading way of measuring call quality/reception. In practice, it was noted that call quality/reception is improved/equal to the 3GS on the 4, regardless of bars (raw signal power).Who cares if you have 1 bar all the time if you're still making calls better than someone with 4 bars?
HTC Incredible owner here.