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Apple Does Slow iPhone Speeds, But For Battery Reasons (Not Sales)

Apple introduced a software feature last year that will crank down iPhone CPU speeds to address crashes that can come from aging batteries.

 & Michael Kan Principal Reporter

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Apple has confirmed it: The company will slow your iPhone down over time.

It's been deliberately cranking down the CPU speeds to address problems that crop up from a device's aging battery, Apple said on Wednesday.

A lithium-ion battery can struggle to meet the peak energy demands as it degrades over time, contains a low charge or endures cold weather. When this happens, the iPhone can crash, potentially damaging the components inside, Apple said.

To offset the issue, the company last year introduced a software feature that scales down the CPU processing, but only when needed. It first applied the fix with the iPhone 6, iPhone 6s and iPhone SE devices. However, Apple has now extended the CPU-capping feature to iPhone 7 devices with iOS 11.2.

"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices," it said.

Wednesday's statement may explain why some iPhone owners believe that their devices slow down whenever Apple releases a new model. (Other experts have attributed the sluggish speeds to iOS software updates.)

However, Apple's statement comes in response to recent claims that replacing the battery in old iPhones will restore the CPU speeds. Last week, one Reddit user noticed an old iPhone 6s showed improved performance when the battery was swapped for a new one.

"From what I can tell, Apple slows down phones when their battery gets too low, so you can still have a full days charge," the Reddit user wrote."

Another post from Primate Labs, the company behind benchmarking software Geekbench, agreed and said iPhones see a software-induced performance dip once the battery ages beyond a certain point.

Apple hasn't offered details behind when the CPU throttling exactly kicks in. The company's full statement is below:

Apple Statement on CPU Issue

About Our Expert

Michael Kan

Michael Kan

Principal Reporter

My Experience

I've been a journalist for over 15 years. I got my start as a schools and cities reporter in Kansas City and joined PCMag in 2017, where I cover satellite internet services, cybersecurity, PC hardware, and more. I'm currently based in San Francisco, but previously spent over five years in China, covering the country's technology sector.

Since 2020, I've covered the launch and explosive growth of SpaceX's Starlink satellite internet service, writing 600+ stories on availability and feature launches, but also the regulatory battles over the expansion of satellite constellations, fights with rival providers like AST SpaceMobile and Amazon, and the effort to expand into satellite-based mobile service. I've combed through FCC filings for the latest news and driven to remote corners of California to test Starlink's cellular service.

I also cover cyber threats, from ransomware gangs to the emergence of AI-based malware. In 2024 and 2025, the FTC forced Avast to pay consumers $16.5 million for secretly harvesting and selling their personal information to third-party clients, as revealed in my joint investigation with Motherboard.

I also cover the PC graphics card market. Pandemic-era shortages led me to camp out in front of a Best Buy to get an RTX 3000. I'm now following how the AI-driven memory shortage is impacting the entire consumer electronics market. I'm always eager to learn more, so please jump in the comments with feedback and send me tips.

The Best Tech I've Had:

  • My first video game console: a Nintendo Famicom
  • I loved my Sega Saturn despite PlayStation's popularity.
  • The iPod Video I received as a gift in college
  • Xbox 360 FTW
  • The Galaxy Nexus was the first smartphone I was proud to own.
  • The PC desktop I built in 2013, which still works to this day.

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