Why is my iPhone going slow? We discover the reasons and solutions

As the fourth law of thermodynamics, an iPhone will begin to slow down over time. Technically the causes are of varied origin and not always usually noticed in time. It is a relatively progressive degradation that affects all the smartphones of other companies as well, and to a greater extent on many occasions.

The reasons can be divided into three major groups: physical degradation, new functions of an operating system that is gradually focusing on more powerful phones, and the accumulation of useful data and “digital junk” in our applications. That is one hardware and two software.

iphone slow
iPhone users have the perception that their phone is slower when a new ‘bigger’ version of iOS (Google Trends) appears

The first has to do with the only component that reduces its performance over the months on a smartphone: the battery. Every time we load it, completely or incompletely, lithium-ion technology loses a bit of capacity. There are dozens of methods that automatically try to repair part of this loss. But it is inevitable in the long term. After the first year, a battery can be 70-80% of its original capacity, but the loss can go further.

We did not notice it because in the day to day the loss is progressive, but many users intuitively remember that the battery lasted longer before. And with this loss of battery, the operating system seems to reduce its performance to consume less energy and try to balance. That seems to be the preliminary conclusion of a study created by analyzing hundreds of iPhone 6s and iPhone 7 with the synthetic Geekbench test. The test is not definitive, there are no control methods in the experiment, but it clearly indicates how there are performance jumps in the processors of an iPhone, supposedly after an automatic reduction in consumption.

iphone slowRepresentation of hundreds of synthetic notes of the performance of iPhones with different versions of iOS, speculatively lower in some cases due to battery degradation. (GeekBench) 

How to Fix a Slow iPhone

What solution does this element have? Change the battery for a new one with the passage of time. Like when you change the oil or car tires, it’s an effective way to regain the performance of the first day. The lost hours will return and, at least part of the lost performance due to the degradation of the same one should return. It’s like a youth pill.


As for the other two reasons cited at the beginning, the new versions of the operating system and the accumulation of data, the solutions are not so easy. Luckily, they are free. Let’s talk first about software updates. Every several months, Apple sends an iOS update, either a “major” update (move from iOS 10 to 11) or a lower one (from iOS 11.1 to iOS 11.2), or even a very minor one like moving to iOS 11.2.1.


This type of updates are mandatory because they usually include security improvements and specific patches, but in other cases, they are accompanied by new software features that are designed for more modern phones. As much as Apple, in this case, try to optimize for all its range of devices, the terminals of years ago will suffer more to have slower processors or less memory to run the news.

This seems to be what happens with iOS 11. Julio César Fernández Muñoz, a veteran programmer specialized in systems from Apple, gives us an example: “Since iOS 10 there is a series of ML (Machine Learning) processes that populate the system. One of them is the predictive keyboard. ” “In iOS 10 they worked on the conventional CPU but now they have created more efficient and more powerful algorithms, based on neural networks” that have a specially designed unit in the iPhone 8 and iPhone X called TPU (Tension Processor Unit) that does not It is present in previous models. This makes the iPhone 6 and iPhone 6s specifically, according to Fernández Muñoz, suffer from performance with a function as simple as typing on the keyboard.

These types of cases will accumulate. New functions in the camera, more powerful web browser, more interactive aspects, etc. that make the operating system consume more and more. In an iPhone of the latest range will always “fetén”, but the rest can resent. What solution do you have? Stopping updating the operating system is dangerous, but updating it can reduce its performance in a visible way. My recommendation, if your iPhone is “old” and it is not a security update … leave it that way. In many cases, it is a lesser evil because unfortunately, and with good reason, Apple does not let “undo” an update easily.

And finally, the last case of degradation is the accumulation of “good” and “bad” data in our applications. With the passage of time and as we use the apps on our mobile, these generate obvious files that we can see: photographs we take, files that we generate, etc. and also other files hidden from our eyes. They are the well-known caches. WhatsApp stores our conversations, Facebook saves the profile photos of our contacts so as not to download them all the time, web browsers do the same with part of the content we have visited, the games generate a lot of information about their models and textures, etc. All these data begin to accumulate.

These elements make our applications go into theory faster, but with the passage of time make the storage fill and the operating system begins to allocate space less efficiently. It is recommended to uninstall those that we never use. Finally, apps have a tendency to “get fatter” with the passage of time adding new features and consuming more resources, this can accumulate and make our mobile feel less light. An intermediate solution is to make a backup of our data, restore the phone and reinstall the applications that are necessary.