Why Xiaomi Mi 9 is slowing down and how it relates to RAM
Your Xiaomi Mi 9 is slowing down, apps are slowing down, and games are slowing down? 90% of the time, the problem is with RAM, which is 6 to 8 GB of RAM (depending on the modification), but even this amount is not enough over time, due to background processes, app cache and MIUI optimization features.
RAM is different from embedded memory (ROM): it is responsible for the speed of tasks in real time. When RAM is clogged, the system begins to “hang” when switching between applications, launching the camera or even scrolling through the feed on social networks. On the Mi 9, this is especially noticeable due to Xiaomi’s aggressive resource management policy: the system tries to keep applications in memory for quick access, but often overdoes it.
Key point: cleanup RAM ≠ You don't make room for photos or music, but you make it back to the smartphone. Below are all the working methods, from basic to advanced, with specifics in mind. MIUI 12/14 and hardware features of Mi 9 (codename).
Method 1: Manual cleaning through the "Safety" menu
The easiest way is to use the built-in MIUI tool, which is root-free and suitable for beginners, and it's important that this option doesn't remove the app cache, it just closes the background processes.
Instructions:
- 📱 Open the Security app (Icon with shield).
- 🔍 Slip on the icon "Optimization" (or "Accelerator" in older versions) MIUI).
- 🧹 Click Clean – the system will show how much memory is freed up (usually 1-3 GB).
- ⚡ Select “Deep Clean” if you want to delete unnecessary cache files.
⚠️ Note: After a deep cleaning, some apps (such as Instagram or Tinkoff Bank) may take longer to load on the next launch – they will have to recover data.
Close important applications (banks, instant messengers)
Save unsaved data (e.g. drafts in Telegram)
Connect to Wi-Fi if you plan to clean up deep
Check the battery level (minimum 20%)
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Method 2: Manually Closing Background Applications
The MIUI system on the Xiaomi Mi 9 aggressively keeps apps in memory even when you’re not using them. For example, Facebook or VK can consume up to 500MB of RAM even when folded. Manually closing helps free up to 1-2GB.
How to do this:
- 👆 Swipe your finger up from the bottom edge of the screen and hold it – the multitasking menu will open.
- 🚫 Scroll left/right and swipe up those apps that you don’t need (like games or social media).
- 🔄 For complete cleaning, tap on the "Close Everything" icon (cross or trash can).
Nuance: Some system processes (e.g. com.miui.home) can't be closed manually. If you see them on the list, that's fine.
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On Mi 9, you can turn on the swipe-down closing gesture. Go to Settings → Additional → Gestures → Multitasking and activate the “Swipe down to close” option.
Method 3: Setup auto-cleaning RAM in MIUI
MIUI has hidden settings that allow you to automatically free up memory when you lock the screen, a feature called "Clear when locked" and is disabled by default.
How to turn on:
- Open "Settings" → "The phone".
- Tap 5-7 times on the MIUI version until the notification “You became a developer” appears.
- Go back to the basic settings, find a new section for developers.
- Scroll down to the "Climates of Processes" block and select "Clean When Locked".
- Set the value "Standard Limit" (or "Aggressive" if the phone is slowing down).
⚠️ Note: In aggressive cleanups, some notifications (such as those from WhatsApp or Telegram) may be delayed because apps will have to restart.
| Cleaning regime | RAM-exempt | Side effects |
|---|---|---|
| Standard limit | 1-2 GB | Minimum (notification delays by 1-2 seconds) |
| Aggressive. | 2-3 GB | Notifications come with a delay, applications open longer |
| No cleaning. | 0 GB | Maximum multitasking, but possible slowdowns |
Method 4: Clearing the application cache (without deleting data)
Application cache is a temporary file that helps programs load faster, and over time, it accumulates and takes up not only space in the internal memory, but also indirectly affects RAM: the system spends resources managing these files. On the Mi 9, the cache can weigh up to 5-10 GB.
How to clear the cache without losing data:
- ⚙️ Go to Settings. → Annexes → Application management.
- 🔍 Choose an app that weighs a lot (like Google Chrome or TikTok).
- 🗑️ Tap "Clear Cache" (not to be confused with "Clear Data" - this will delete accounts and settings!).
- 🔄 Repeat for top-10 The most "heavy" applications (they can be sorted by size).
Critical information: On the Xiaomi Mi 9, the cache of system applications (for example, com.android.systemui) is not recommended to be cleaned - this can lead to interface failures.
What applications can be cleaned without risk?
Method 5: Using a developer to limit processes
For advanced users, MIUI offers tools to limit background processes, which allows you to manually control how many applications can be hanging in RAM at a time.
Step-by-step:
- Activate the Developer Mode (as in Method 3).
- Go to Settings → For Developers → Process Limitation.
- Choose one of the values: Process maximum 2 is radical RAM savings (suitable for weak devices); Process maximum 3 is the balance between performance and multitasking; Standard limit is the default value.
Restart your phone to apply the changes.
⚠️ Note: When limited to 2 processes, some applications (such as music players or navigators) will be closed when switching to another task.
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The optimal value for the Xiaomi Mi 9 is “Practice 3 Maximum.” This will free up to 1.5 GB of RAM without critically damaging multitasking.
Method 6: Disable Auto-Run Unnecessary Applications
Many apps (especially Chinese ones) automatically start when the phone is turned on and hang in the background, consuming RAM. On the Mi 9, this can be banned.
Instructions:
- 🛡️ Open the Security" → "Auto-start".
- 🔍 View the list of applications with auto-start right.
- ❌ Disable Autoplay for Unnecessary Programs (e.g. AliExpress, Wildberries, Games).
- 🔄 Pay attention to system applications – they do not need to be touched!
Example: Disabling Facebook AutoRun can free up to 300-500MB of RAM each time you turn on your phone.
Method 7: Reset to factory settings (last resort)
If all of the above methods didn’t work, and the Xiaomi Mi 9 is still slowing down, it could be the problem with the system debris that has accumulated over the years of use, in which case hard reset will help.
⚠️ Warning: This procedure will delete all data from your phone, including photos, contacts and apps. pre-backup through Settings → The phone. → Backup or Mi Cloud Backup.
How to reset your settings:
- Go to Settings → About the phone → Reset settings.
- Select "Erase all data."
- Enter your password (if installed).
- Confirm the action and wait for the reboot (it will take 5-10 minutes).
Once reset, the phone will be like new. Install only the apps you need and keep track of RAM filling with built-in tools.
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The factory reset on the Xiaomi Mi 9 returns the original 6-8GB of free RAM (depending on the modification), which is guaranteed to solve performance problems, but takes time to set up the phone again.