My iPhone X has become very slow. What could be the cause and what remedies are available?

Because at 80% Maximum Capacity, Apple recommends that you replace the battery......for good reason.

In other words, although you might see that the battery is at "max charge", that charge is nowhere near where it was a few months ago, even though the numbers might look similar.

A new battery is $89 (US). Make an appointment at the Apple Store or take the phone to an authorized Apple Service shop. You can find a list of authorized service shops in your area using this link:

Find Locations

To add to H1290’s reply above, if the battery health is 80% or lower, you’re headed for a battery replacement.

Battery service details: iPhone Battery Repair & Replacement - Apple Support

Hello Patomalo!

What is the Maximum Capacity of your device’s battery? To find it, go to: Settings > Battery > Battery Health & Charging. 

Looking forward to your reply!

Patomalo Said:

"My iPhone X has become very slow. What could be the cause and what remedies are available?: The iPhone takes a long time to load applications. I have plenty of empty storage available."

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Troubleshooting an Overheating Phone:

Close All Apps:

An app may be eating up your system resources. Hold you finger down as you swipe up from the bottom-left corner, to the top-right corner. Then, close all of these open apps, by swiping up quickly for each app.