Apple's iPhone chips aren't as different as some have reported

Though some testing showed "identical" iPhones performing significantly different, depending on internal chips, the differences are actually quite minor.

iPhone 6
Image: Bill Detwiler/TechRepublic

With Apple selling millions of iPhones per quarter, the company uses several different manufacturing partners to build its phone. Two of those partners are Taiwan Semiconductor Manufacturing Company (TSMC) and Samsung--yes, the same Samsung that makes the popular Android smartphones and tablets.

Ever since the iPhone 6s and 6s Plus were released last month, teardown specialists like iFixit and Chipworks have been looking deep into what makes the devices tick.

One of the more surprising discoveries was that Apple wasn't just using multiple manufacturing partners for its different chips, it was using two different manufacturing partners for chips within otherwise identical smartphones. That is, you could buy one iPhone 6s and receive an A9 chip built by Samsung, and then purchase a second one and get a processor from TSMC.

These aren't identical processors either. Samsung is using a smaller, 96 square mm die while TSMC's A9 is 104.5 square mm.

As Chipworks notes:

"For Apple to go through all the trouble of dual-sourcing a custom designed part and launching on day one with both parts, suggests major sourcing problems. For cost and power reasons, there is little reason to run a larger die, unless the smaller die was not available at the right volumes."

Now, aside from chip nerds, most buyers of the iPhone 6s and 6s Plus won't care who makes their mostly identical phones... unless there's a performance difference. Unfortunately, that's what some users have found when stress-testing their phones.

It turns out that some users were discovering signficant performance differences between the two chips, with the TSMC-manufactured A9 displaying significantly longer battery life than the Samsung chip under a heavy processor load.

Obviously, this would be concerning for many iPhone buyers. However, Apple says these tests aren't reflective of real-world battery life, as most iPhone users won't run their processors at full tilt for hours at a time.

Instead, Apple says its own internal data and testing, plus anonymous testing collected from its millions of customers, show battery life variances of just 2-3%, which is well within its manufacturing tolerances, even for devices with identical components.

According to a statement given to TechCrunch:

"Certain manufactured lab tests which run the processors with a continuous heavy workload until the battery depletes are not representative of real-world usage, since they spend an unrealistic amount of time at the highest CPU performance state. It's a misleading way to measure real-world battery life. "

Testing by Ars Technica largely confirmed Apple's account, showing that iPhone 6s models with chips from TSMC and Samsung performed very similarly on battery life tests. The site noted that "most of the time, iPhone 6s battery life should be similar, no matter which chip your phone is using."

Andre Cunningham, the writer of the Ars piece, notes that he isn't worried about using his own iPhone, even though it has the Samsung chip in it.

Though it appears not to matter too much, if you'd like to determine which chip your iPhone 6s and 6s Plus have inside, you can download Lirum Device Info Lite from the App Store. Open it up and, on the main screen, you'll see a model number. If it's N71mAP or N66mAP, you have the TSMC chip. N71AP and N66AP are from Samsung.

Are you concerned about the different processors in your iPhone 6s? Let us know your thoughts in the discussion thread below.

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