How to check the memory status on Xiaomi Mi 9: RAM, ROM and cache

The Xiaomi Mi 9, released in 2019, is still popular with users thanks to its powerful hardware: Snapdragon 855 processor, 6-8 GB of RAM and 64-256 GB of internal storage. However, over time, even flagship devices begin to “brake”, and the fault is often overloaded memory. How do you know what the problem is? Where to see the current state of RAM (RAM) and ROM (internal storage), and how to clean the cache without harming the system?

In this article, you will find current ways to check memory on Xiaomi Mi 9 with the features of MIUI 12-14 (including global and Chinese versions of firmware).We will analyze both standard methods through phone settings, and advanced methods using ADB, third-party utilities and hidden menus of engineering mode. We will pay special attention to the diagnosis of “leaks” of RAM and analysis of storage employment by category (applications, media, system data).

1. Memory check through standard MIUI settings

The easiest way to do this is to use the built-in MIUI tools, which provide basic information about memory status, but often enough for initial diagnosis.

Open the Settings app (cog icon) and go to About Phone, and you're interested in two things:

• 📱 General information → Memory: shows the volume of the ROM (internal storage) and its occupancy. On Mi 9, the section for the ROM is displayed here. MIUI Optimized Storage (optimized storage) if the function is active.
• 🔄 Status of the system → Memory usage: Real-time RAM loading graph. Click on it to see a list of applications that consume the most RAM.

Note the line Available in the memory section. If the free space is less than 10-15% of the total, the system will start to “brake” due to lack of cache space and temporary files, in which case it is recommended to clear unnecessary data (more about this in section 4).

2 Detailed Memory Analysis Through "Security"

The Security (Shield Icon) app in MIUI offers advanced memory monitoring tools, pre-installed on all Xiaomi smartphones, including the Mi 9.

1. Open Security → go to the Optimization tab.
2. Slip on Memory (or Storage in newer versions of MIUI).
3. The system will automatically scan the device and show:

The Clean button is also available in this section, which removes cache and junk files, but be careful not to clear the cache of system applications (e.g. com.android.systemui) as this can cause MIUI shell to malfunction.

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If there is no “Optimization” tab in the “Security” section, update the app via Google Play or the MIUI App Store. The interface may differ in older versions.

Advanced diagnostics via engineering menu (#4636##)

The hidden engineering menu allows you to get technical data about the state of memory that is not available in standard settings.

1. Launch the Phone app.
2. Enter the combination: ##4636## (no call).
3. Select the item Information about the phone (or Usage statistics in English firmware).

Here you will see the Memory section with detailed statistics on RAM:

• 📊 MemTotal: total RAM (for Mi 9 – 6 or 8 GB).
• 📉 MemFree: free memory (optimally - at least 1-1.5 GB).
• 🔄 Buffers/Cached: memory occupied by the cache of the kernel and buffers (it can be considered "conditionally free»).

If MemFree is consistently close to zero (less than 300-500 MB), this indicates a memory leak – one or more applications do not release RAM after closing, in which case it will help to restart the device or force the problem programs to stop through Settings → Applications.

4.Memory Cleanup: What Can Be Deleted Without Risk

If the analysis shows a memory deficit, the first thing to do is to make room, but it should be done competently so as not to disrupt the system.

Here is what we do not recommend to touch:

• 🚫 Files in folders /system, /vendor, /data/app (system-data).
• 🚫 Cache applications com.miui, com.android.systemui (may cause shell failures).
• 🚫 folder MIUI at the root of the storage (contains themes and system settings).

For deep cleaning, use Files by Google (available on the Play Market) to find:

• 🗑️ Temporary files (remains after updates, browser cache).
• 📁 Large files (video, archives, unused files) APK).
• 🔍 Duplicates (repeated photos or documents).

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Before a mass cleanup, back up important data through Settings → Additional → Backup. This will prevent the necessary files from being accidentally deleted.

5. Memory monitoring via ADB (for power users)

If you want the most accurate memory status, you can use the Android Debug Bridge (ADB) tool, which requires connecting your smartphone to your computer, but you get information that is not available through the GUI.

To start, turn on USB debugging:

1. Activate Developer Mode (7 times tap the build number in Settings → About phone).
2. Return to Settings → Additional → For developers and enable USB debugging.

Now connect the Xiaomi Mi 9 to your PC and execute the following commands in the terminal (or Command Prompt):

adb shell dumpsys meminfo


adb shell df -h

The first team will provide detailed statistics on RAM, including:

• 📌 Native Heap: memory occupied by native processes.
• 📌 Dalvik Heap: memory used by Android virtual machine.
• 📌 Private Dirty: The “dirty” memory that can’t be uploaded to the disk.

The second command (df -h) will show the status of the ROM by section (e.g. /data, /system). Note the Available column, which is the real available space for user data.

⚠️ Note: Do not use the commands adb shell rm or adb shell pm uninstall without understanding the consequences. Deletion of system files can lead to a blink (inoperability) of the device.

6. Applications for memory analysis: top-3 utility

If standard MIUI tools aren't enough, you can install third-party apps that offer more visualization and additional features like automatic cleaning on schedule. Here are the proven options for Xiaomi Mi 9:

When using SD Maid, look at the CorpseFinder partition, which finds residual files from remote applications that often take up hundreds of megabytes. And AccuBattery's Deep Sleep graph is useful: if the phone rarely goes into deep sleep, it can indicate background activity of applications that consume RAM.

⚠️ Warning: Some cleaners (such as Clean Master) aggressively remove cache, which can slow down the system. MIUI already has built-in optimization mechanisms, so cleaning 1-2 times a month is enough.

FAQ: Frequent questions about memory on Xiaomi Mi 9