Redmi 9 smartphones have become a popular choice among users looking for a balance between performance and price. However, over time, the use of apps, the accumulation of photos and the installation of heavy games inevitably lead to a lack of space. When the device starts to run slower, the first thing to understand how much resources are still available and what exactly occupies space.
With MIUI, which is installed on Xiaomi Redmi 9, file and system resources management is implemented through a user-friendly but sometimes confusing interface. Users are given several ways to monitor the state of storage, from standard widgets on the desktop to deep analysis in the engineering menu. Understanding the difference between RAM and internal storage (ROM) is critical to properly diagnosing problems.
In this article, we will take a closer look at all available methods for checking the amount of free memory, learn how to distinguish system files from user data, learn how to identify hidden messenger caches, and be able to effectively manage the space of your device without installing third-party software.
The difference between RAM and ROM in Xiaomi smartphones
Before we get to practical action, we need to clearly distinguish between two types of memory that are often confused by beginners: RAM (RAM) is a short-term storage where data from running applications is temporarily stored. The more it is free, the faster programs are switched and multitasking works more stable. On Redmi 9, the amount of RAM varies from 3 to 4 GB depending on the modification.
Internal memory (ROM or flash memory) is used to permanently store all your files: operating system, installed applications, photos, videos and music, and this is the lack of it most often felt by the user when they receive notifications that the place is running out. Unlike RAM, data in ROM is stored even after the device is completely powered off.
Android’s MIUI-based system dynamically allocates resources, and if RAM is scarce, it forces the background processes to close, which can cause twitching of the interface, while the lack of internal memory makes it impossible to install updates, create new photos or cache applications correctly.
Memory check through the standard Security application
The fastest and most reliable way to know the state of storage is to use an embedded system tool. In the MIUI shell, the Security app acts as not only an antivirus, but also a memory manager. It provides aggregate data that the average user understands without having to dive into technical wilds.
To access the information, open the app menu and find the shield and lightning icon. When you run the app, you'll see the main screen with the "Clean up" button. But what we're interested in is not the cleaning itself, but the detailed statistics. Press the Cleanup button and the system will do a quick scan. Once you've finished scanning, you'll see a pie chart showing the percentage of occupied and vacant space.
Click on this diagram or volume text (e.g., “45GB of 64GB occupied”) to go to the detailed Storage section, where the system will prompt you to delete unnecessary files, but also show a detailed breakdown by category, and you can see how much space apps, images, videos, documents and system debris take up.
☑️ Verification through the Security Application
It is important to note that the data in this section is not updated in real time, but only at the request of the user or when you start the scan. If you just downloaded a large file but did not run the analyzer, the numbers may remain the same until the next scan.
Analysis of storage through system settings
A deeper level of information is available through the standard Android settings menu, which is useful when you need to understand which application consumes the most resources and decide whether to delete or clean the data, and here the information is presented in a more structured form, divided by content types.
To get into this section, go to Settings and scroll down to About Phone. In the menu that opens, look for the Warehouse (or Memory) line. Clicking on it will show you a timeline for the last days or weeks, as well as exact figures for total volume, system files and free space.
Unlike the Security app, you can see the application-specific breakdowns, and it shows you a list of programs that's sorted by the amount of space you take up, and if you click on any application, you can see the details of the size of the application itself, the amount of user data, and the size of the cache, and it allows you to pinpoint the bloated social media caches without deleting the app itself.
Why is the volume in the settings less than the stated?
Also in this section, you can see information about the SD card, if installed. The system clearly separates the internal storage and the external card, allowing you to transfer some types of files (photos, music) to an external medium, freeing up precious internal space for the system to work.
Use of the Engineering Menu for Detailed Diagnostics
For advanced users who don't have enough standard reports, there's an engineering menu, a hidden part of the system that's designed to test hardware components, and you can get technically accurate information about the state of memory chips, their temperature, and the number of write cycles, although you need to be careful about interpreting the data.
To enter the engineering menu on Xiaomi Redmi 9, open the Phone app and enter a special code: ##6484##. Immediately after entering the last digit, the CIT menu (Customer Information Test) will open.
Inside the memory tests, you can run a read-write error check, especially if the phone is starting to be unstable, spontaneously restarting, or files are getting damaged, but beware: some tests can take a long time and load the processor.
⚠️ Note: Do not change the settings in the engineering menu unless you are sure of your actions. Resetting calibrations or changing the parameters of the memory controller can lead to unstable operation of the device).
The data in the engineering menu is often presented in hexadecimal code or specific technical units. The average user needs to know that the status should be Pass or OK. If tests show errors, this indicates physical wear of the memory chip, in which case software cleaning will not help - you need to replace the component in the service center.
Table: Memory distribution in different versions of Redmi 9
Redmi 9 range came in several configurations. It is important for users to understand how much is available out of the box for their particular version, so as not to demand the system impossible. Below is a table with approximate values of available memory after installing all system updates.
| Model of the device | Claimed ROM volume | Available to the user (approximately) | RAM volume |
|---|---|---|---|
| Redmi 9 (Global) | 32GB | ~19.5 GB | 3GB |
| Redmi 9 (Global) | 64GB | ~51.0 GB | 4GB |
| Redmi 9C | 32GB | ~19.8 GB | 2GB |
| Redmi 9A | 32GB | ~20.1 GB | 2GB |
As you can see from the table, the difference between the declared and available volume can be up to 30-40%, which is due to the fact that manufacturers consider 1 GB equal to 1000 MB, and the operating system is 1024 MB, plus the MIUI system itself and Google preinstalled services.
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Always focus on the available volume, not the model name, as the system takes up a significant part of the space.
Cleaning and optimizing occupied space
Once you know that memory is busy, it becomes a question of releasing it. Simply removing applications often doesn't work because they're mostly data-driven. The most effective method is to use Deep Clean in the Security app, which finds duplicates, similar photos, and old APK installation files.
Telegram, WhatsApp and Viber have their own built-in memory management tools, such as Telegram, where you can go to Settings → Data and Memory → Memory Use and clear the cache without deleting the correspondence. This can free up several gigabytes of space instantly.
It is also recommended to check the Downloads folder, often forgetting downloaded documents, game installers or advertising files that lie dead for months, and removing the contents of this folder is safe and often has a significant result.
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Use the Cache Clear feature regularly, but at least once a week, to prevent the accumulation of temporary files that slow down the system.
If even after cleaning the place ends, consider transferring media files to cloud storages such as Google Photos or Yandex.Disk. Set up automatic synchronization with subsequent removal of photos from the device is the best way to keep eternal memory on Redmi 9 free.
⚠️ Note: Before clearing the application data (not the cache, but the data), make sure you remember your logins and passwords. This operation will completely reset the application in the post-installing state, removing all your correspondence and settings inside it.