Owners of the popular Xiaomi Redmi Note 9 smartphones often face the need to monitor the free space on the device. Over time, internal memory is filled with junk files, app cache and heavy multimedia data, which can significantly slow down the MIUI operating system. Understanding how many gigabytes are available for use is the first step to optimizing the performance of the gadget.
There are several proven ways to find out the exact amount of occupied and vacant space, as well as get detailed information about RAM. In this guide, we will examine in detail the regular system tools, hidden engineering menus and third-party utilities, you will learn not only to look at the numbers, but also to interpret them correctly for effective management of resources of your smartphone.
Standard analysis through system settings
The easiest and most reliable way to know how much space is left on your Redmi Note 9 is in the standard settings menu. Android in the MIUI shell provides fairly detailed statistics that are updated in real time. To access this information, you need to open the main menu and find the Settings icon, usually located at the top of the list or on the desktop.
Once you log in, scroll down to About Phone, and that's where you get all the basic configuration information on your device, and click on Warehouse, and the system will instantly calculate the space you're occupying, and you'll see a pie chart that visually shows the ratio of system files, apps, images, videos, and other debris.
Detailing allows you to understand what is eating away precious gigabytes. If you see a “Other” section taking up suspiciously much space, it may indicate the accumulated messenger cache or residual files of remote programs. In the same window, a Cleanup button is often available, which automatically prompts you to delete temporary files.
⚠️ Note: When using built-in cleaning, carefully look at what the system suggests to delete. Sometimes important files from the Downloads folder that you do not want to lose are included in the list.
Don't ignore this section by going in at least once a week, and regular monitoring helps prevent critical disk filling that can cause the phone to start to run unstable or stop receiving calls and messages altogether.
Checking RAM through the developer menu
If the internal memory is responsible for storing files, then RAM (RAM) affects the speed of switching between applications and multitasking. In the standard interface of Redmi Note 9, information about the use of RAM is hidden from the average user, but it can be activated through the developer menu, which will give you access to a floating window showing the percentage of RAM load in real time.
To enable this feature, go to Settings → About Phone and find the MIUI Version line. You need to quickly click on this line 7-10 times in a row until the notification “You became a developer” appears. Then a new option will appear in the main settings menu Additional, and inside it – Advanced Settings.
Inside the Advanced Settings section, look for Memory Status or Memory Use. Activate the Memory Use Switch. Now, your smartphone screen, usually in the upper left corner, will display a fraction (e.g., 3.2/4.0 GB) showing the current system load.
Why monitor RAM?
This tool is especially useful when testing heavy games or working with resource-intensive applications, and you can see how quickly the buffer is filled and how efficiently Redmi Note 9 manages running processes.
Using the Security App for Analysis
Each Xiaomi smartphone has a Security system app preinstalled, which acts as an antivirus and an optimizer, and it's one of the most convenient tools for quickly evaluating memory status without going into deep settings. Launch the app and select Clean up on the home screen.
Once scanned, the system will give a detailed report of how many megabytes or gigabytes can be freed up, and it will show the total amount of internal memory used as a percentage, and the app will automatically sort files into categories, allowing you to quickly find and delete large videos or unnecessary.apk installation packages.
The Deep Cleanup section, which analyzes the content of messengers (WhatsApp, Telegram, Viber) and shows how much space is occupied by the images and videos viewed but saved, is often where tens of gigabytes of unnecessary garbage are hidden.
☑️ Checking the vault
Importantly, the algorithms of this application can be aggressive, and it can suggest removing the cache of cards or browsers, which will lead to the departure of authorization in some services. Always check what is marked with the tick before the final confirmation of deletion.
Detailed statistics on file types
For those who like accuracy, MIUI offers a breakdown of the storage by content type, which allows you to understand the structure of the disk filling. Going to the storage settings, you will see a list of categories: Apps, Images, Videos, Audio, Documents, etc. Clicking on any of the categories opens a detailed list of files, sorted by size.
Users are often surprised to find that the Video section takes up the lion's share of space, not just videos taken, but also automatically saved statuses from WhatsApp or cache from YouTube. Deleting old video files is the fastest way to free up a few gigabytes.
The App section shows not only the size of the installation file, but also the amount of data that the program has accumulated during operation, for example, navigators can take up hundreds of megabytes of offline maps, and streaming services can take up downloaded music.
| Type of data | Description | Recommendation |
|---|---|---|
| System files | Android operating system files and MIUI shells | Do not touch, removal will lead to failures |
| Annexes | Established programmes and their data | Remove unused, clean up heavy cache |
| Images | Gallery photos and screenshots | Move to the cloud or PC, remove blurred |
| Audio/Video | Music, movies, recordings of the recorder | Remove or remove if not necessary |
| Others. | Cash, temporary files, archives. | Requires manual check before removal |
This detail helps to identify the hidden eaters of space, for example, you may find that the Documents folder contains old presentations or PDF-Files that you no longer need, but they take up space.
Third-party monitoring applications
Staffing is not always enough for deep analysis, especially if you want to find specific files hidden in the system folders, in which case third-party utilities from Google Play come to the rescue. One of the most popular and informative is the DiskUsage program or its modern counterparts, such as Storage Analyzer.
These applications build a visual memory card, where each file is represented as a rectangle, and the larger the file, the larger the area it occupies on the screen, and this allows you to instantly find forgotten archives or error logs that can weigh several gigabytes.
Another useful tool is CPU-Z or AIDA64, which provides technical information not only about memory, but also about the processor, sensors and temperature, and the Memory tab in these applications will show the type of memory (LPDDR4X), frequency and current load of channels.
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When installing third-party memory analyzers, read permissions carefully, and many require access to all files on the device, which may not be secure from a privacy perspective.
The use of such programs gives the advantage of more flexible sorting and the ability to search for duplicate files, which is not always done efficiently with regular Redmi Note 9 tools.
Cache cleanup and storage optimization
Once you've figured out what memory is, you need to clean it up, and the safest method is to clean the app cache, and cache is temporary data that speeds up programs, but can inflate to incredible sizes over time.
To clean up, go to Settings → Apps → All apps. Select a heavy app (like Instagram or TikTok), click Memory and select Clear Cache. Don't confuse it with the Clear All button, as the second option will reset the app to a state after installation, and you will have to re-enter logins and passwords.
Also worth checking is the Download folder, which often automatically saves files from the browser or documents received through messengers, and cleaning this folder regularly is a good habit for maintaining order in the system.
⚠️ Note: Do not delete files with the.obb or.data extension from Android system folders manually unless you are sure of their purpose.This can cause games and applications to stop running.
If the memory is still filling up too quickly after all the manipulations, you may want to consider resetting to factory settings, but make sure to back up your important data to a cloud service or computer before doing so.
Expanding Memory with a MicroSD Card
The Redmi Note 9 features a hybrid slot that allows you to use a microSD card, which is a great solution for those who lack built-in storage for photos and videos, and installing a card instantly increases the available space for media files.
Once you have the card installed, the system will suggest formatting it, so you can choose to use it as Portable Storage (for photos, music, video) or Internal Storage. The second option allows you to transfer the apps to the map, but the card will only work with this phone.
It is important to choose memory cards with high write speed (class U3 or V30). Slow cards can cause interface slowdowns and a long load of the gallery, as the system will try to read data at a low speed.
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Using a high-quality microSD memory card is the most budget-friendly way to increase the storage volume for multimedia, but you should not count on a significant acceleration of the smartphone itself.
Remember, memory cards are less reliable than embedded flash memory, and don’t store single copies of important documents or family archives on them without additional backup in the cloud.