Owners of Xiaomi’s flagship Mi 9 smartphone often face the need to know exactly how much free space the operating system has left in its possession. This is critical for device performance, as a crowded drive leads to noticeable delays in the interface and reduced speed of writing new data. Standard display methods can show non-obvious numbers, raising questions about where exactly the gigabytes claimed by the manufacturer disappeared.
Understanding the structure of the MIUI-based Android file system allows you to manage resources efficiently. In this article, we will discuss in detail all the available ways to check the amount of RAM and internal memory, explain the difference between declared and real values, and consider hidden engineering menus for advanced users.
Standard ways of checking through system settings
The most obvious and safe way for the average user is to use the standard operating system interface. To get basic information, you need to go to the main settings menu of your smartphone, which is usually at the bottom of the list or accessible through a gear in the notification curtain.
The list that opens is about the phone, and it's about the processor model, the Android version, and most importantly for us, the storage settings, and if you click on a line that shows the volume, like 64GB or 128GB, you'll go to a detailed menu.
Here, the system displays two main categories: Internal storage and RAM. Internal storage shows how much space is occupied by applications, photos, videos and system files, and how much is available to the user. RAM shows the current RAM loading by running processes.
⚠️ Note: The available memory numbers in the standard menu may differ slightly from the actual physical volume due to the file system formatting features and reserved system partitions.
It is worth noting that the MIUI shell sometimes hides some technical information to make it easier to understand. If you want more detailed statistics by file categories (for example, separately the size of the messenger cache or the amount of system debris), you should use the built-in Security application and the Cleanup function.
Use of the Developer Menu and Statistics
For users who don't have enough standard data, you can activate an extended settings menu, which allows you to access more in-depth statistics on CPU and memory usage, and to activate this mode, you need to go to Settings → About phone and quickly press the MIUI build number 7 times in a row.
Once you have become a developer, a new option will appear in the Settings menu, which will select the Developer section, and scroll down to the Applications section, and you can find Process Statistics or Memory Use.
This section shows you a list of all the applications that are running, with the exact amount of RAM they are using in real time, and it's an invaluable tool for identifying parasitic programs that are consuming resources in the background, even if you're not using them right now.
Why do you need a developer menu?
It is important to understand that changes in this section may affect the stability of the device. Dalvik/ART, If you're not sure what the consequences are, you can reset this menu by simply turning off the tumbler at the top of the screen.
Technical reasons for discrepancy in memory
Many users notice that when buying a smartphone labeled 128 GB, only about 110-115 GB is available for use. This is not a defect or a fraud on the part of the manufacturer, but due to fundamental differences in the calculation systems.
Drive manufacturers use a decimal number system where 1 gigabyte is 1,000,000 bytes. At the same time, the Android operating system and computers use a binary system where 1 gigabyte (GB) is 1,073,741,824 bytes (1024 megabytes), a mathematical difference of about 7% of the total.
In addition, a significant portion of the space is occupied by the operating system itself, device drivers, pre-installed Xiaomi applications and Google services, which are necessary for the correct operation of the Mi 9 and cannot be deleted by standard methods without loss of warranty or functionality.
Below is a table showing the real available space for different Xiaomi Mi 9 configurations after initial setup:
| Claimed amount | Systemic calculation (decimal) | Android Calculation (Binary) | Available to the user (approximately) |
|---|---|---|---|
| 64GB | 64,000,000 bytes | ~59.6 GB | ~48-50GB |
| 128GB | 128,000,000 bytes | ~119.2 GB | ~108-110 GB |
| 256GB | 256,000,000 bytes | ~238.4 GB | ~225-228 GB |
⚠️ Warning: Do not attempt to format system partitions through a computer to "free up" space, this will result in the total inoperability of the smartphone and loss of warranty.
Modern versions of MIUI can use the F2FS file system instead of ext4, which improves speed, but may slightly change the way free space is calculated due to the peculiarities of block allocation.
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The difference of 10-15% between the declared and actual volume is normal, due to mathematics and system files, not a defect of the device.
Checking through the engineering menu and diagnostic codes
To get the most accurate technical information about the state of the drive, you can use the engineering menu, which is a hidden interface designed for service engineers, but accessible to all users through a set of special devices. USSD-code in the appendix "Phone».
Type the code ##6484##. Immediately after entering the last digit, the menu will open. CIT (Customer Integration Test. Here is a complete list of tests of all components Xiaomi Mi 9. Find the item associated with internal memory (Internal Storage) or SD-map, if it is installed.
Unlike the standard menu, CIT shows the technical parameters of the memory chip, including temperature, read/write speed, and the number of rewrites cycles, which is useful for diagnosing faulty sectors or the degradation of the drive over time.
☑️ Diagnosing Memory Through Memory CIT
Alternative code ##4636## opens the testing menu, and you can see battery status and some usage options on the phone, but the file system is less detailed than CIT.
Third-party applications for detailed analysis
If built-in tools are not enough, specialized utilities come to the rescue from the Google Play store. Apps like DiskUsage, Storage Analyzer or AIDA64 provide visualization of occupied space in the form of graphs and diagrams.
Programme AIDA64 Allows you to provide detailed hardware features of the Mi 9. OS → Storage displays not only the total volume, but also the file system type, cluster size and support status. TRIM, longevity SSD-accumulator.
Disk analysis utilities like DiskUsage build a memory card where each rectangle corresponds to a folder or file, which allows you to instantly find “heavy” forgotten downloads, video cache or remnants of remote games that take up gigabytes of space.
But be careful with cleaner apps, many of which aggressively remove cache, forcing apps to re-upload data, consuming traffic and time, and using Xiaomi’s built-in Security tool, which is optimized for MIUI, is better.
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Use the DiskUsage app in Size Sort mode to find the biggest files hidden deep in Android and Data folders in seconds.
Optimization and management of the file system
Once you know where to look for memory on Xiaomi Mi 9 and find out that it is full, you need to perform a competent optimization. Simply removing photos does not always give the desired effect, unless you touch the system debris.
First, clear the Download download folder and the messenger cache (WhatsApp, Telegram) as they tend to grow to giant sizes. MIUI storage settings have a Cleanup feature that automatically finds such files.
If the space is critically small (less than 2-3 GB), the system may start to work unstable, in which case it is recommended to transfer media files to the cloud service Google Photos or Mi Cloud, or to the computer, freeing up internal space for system operations.
Regularly restarting the device also helps to clear temporary files and process fragments that may freeze and take up RAM. Do this at least once a week to keep the flagship running.