There are a number of reasons why the Galaxy S9 or Galaxy S9+ can show signs of slow performance, overheating while playing a game, or just bad battery life in general. A great troubleshooting step to resolve these more common issues is to clear the cache partition of the device.

Android, and smartphones in general, have evolved into complex computer systems that actually need to be optimized better than a desktop or laptop PC. Since these mobile devices have a small battery and a weaker CPU compared to other computer options, the smallest conflict can completely change the way our smartphone behaves.

Apple does a good job at keeping these things under control (as best as they can) by locking as much freedom away from 3rd-party applications as possible.

This ends up allowing for less customization options but it does a lot to keep some of the more vital hardware limitations in check. Now, I recently showed you how to boot the Galaxy S9 into Download Mode as that is generally the first troubleshooting step you should do if you notice overheating, a bad battery or slow performance. However, this just gives you an idea as to what is causing the issue instead of fixing it. Today I’ll be showing another troubleshooting related to these issues but this cone can actually fix it in some cases.

Clearing the Cache Partition of the Galaxy S9

  1. Boot the Galaxy S9 into Recovery Mode
  2. Press the Volume Down button until you highlight the Wipe Cache Partition option
  3. Then press the Power button to select it
  4. Press the Volume Down button to confirm you want to wipe this data
  5. And press the Power button again to select the Yes option
  6. Once complete, the menu should appear at the top again
  7. Make sure the Reboot System Now option is highlighted
  8. So you can press the Power button to reboot the Galaxy S9 back into Android


If you’ve been following along in my previous Galaxy S9 and Galaxy S9+ guides then you’ll notice that this isn’t a complicated tutorial at all. The most complicated part is to boot the smartphone into Recovery Mode and that is done by first powering down the device. When completely off, we then want to press and hold the buttons mentioned in the linked page of Step 1 and we’ll be taken to the stock Android Recovery Mode menu once it passes through the initial boot cycle.

From here, we can’t control the screen with touches so we need to use the Volume Up and Volume Down buttons to control which menu option is highlighted. In this case, we want to highlight the Wipe Cache Partition option so we just need to press the Volume Down button a few times to get there. When ready, press the Power button to select this option and be ready to be greeted with a confirmation screen. Samsung wants to make sure you actually want to proceed so be sure to highlight the Yes option and then press the Power button again to select it.

Galaxy S9 Wipe Cache Partition
You’ll see this text appear in the bottom left corner to show you what it’s doing and when it is done.

This process shouldn’t take more than 3-5 seconds before the menu appears at the top of the screen again. The task that was completed (formatting /cache) will be displayed at the bottom left though, so you can watch for that if you want. When it’s completed, the Reboot System Not option should be highlighted by default so press the Power button again unless you have something else you need to do in the stock Android Recovery Mode. Pressing the Power button here will reboot the Galaxy S9 and take us right back into the regular Android operating system.

What it Does

Over the last couple of weeks I have been showing you how to boot the Galaxy S9 and Galaxy S9+ into a number of special boot modes. Some, like Download Mode, will not be useful for people who do not have the desire to customize their device or manually flash an official firmware from Samsung. However, there are some special boot modes, like Safe Mode and Recovery Mode, that everyone should at least be aware of. Even if you don’t ever plan on using them, these modes are something you should know about.

The applications and games we have installed on our device store various pieces of data in the /cache partition so that it can display this information quickly the next time you open it up. Without this setup, the CPU would need to calculate and generate all of this information over and over again each time you launch the app. So allowing applications to store and pull information from the /cache partition not only makes the phone perform faster and uses less battery life as well.

Now, there are times when an application stores the wrong type of data in the /cache partition. This can be caused by a number of things such as a random bug or from it being poorly coded in the first place. There are also times when data stored on this partition becomes corrupt as well. No matter what issue causes this, the application is expecting to retrieve a certain piece of data while it’s actually receiving something else (sometimes something that is completely unreadable).

Why it Works

So if this ever happens to you then it can cause the application or game to freak out and perform poorly. Some applications will continue to try and grab that data from the cache partition until it gets the right data. This causes the application to loop over and over again and can result in poor battery life, poor performance, or even overheating in some cases. The goal here is to wipe the cache partition of the Galaxy S9 so that all of your applications need to rebuild that cached data when it’s opened again.

This wipes the cached data for all applications but there is a way to manually do this for individual applications. I’ll be covering this in a future tutorial as it is helpful when you know the exact application that is currently having issues. Usually it’s difficult to pin down so simply wiping the entire partition is a much better option here.

Experiencing difficulties with your Device, check out our “How To” page on how to resolve some of these issues.


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