Why Xiaomi Redmi Note 9 is dumb: analysis of causes and working ways to eliminate

Your Xiaomi Redmi Note 9 Suddenly it started to hang, apps opened with a delay, and interface animation twitched? This problem is familiar to many owners of budget Xiaomi smartphones through the Internet. 1-2 Unlike the flagship models, the Helio processor is the first to be used. G85 and 4 GB of RAM in Redmi Note 9 have a limited margin of performance, which over time is exhausted due to the accumulation of digital debris, firmware errors and unoptimized updates MIUI.

But don't rush to write off the device! 80% In this article, we will discuss the problems of brakes, which are eliminated by software methods without contacting the service center. 10 Key causes of slowdown — from a trivial lack of memory to hidden errors of the Android kernel, and also give step-by-step instructions with visual hints. MIUI 12-14 For the Redmi Note 9, which are not dokumented in official manuals.

1. RAM overload: why 4GB is already missing

The main reason for the brakes Redmi Note 9 — It's a memory deficit, even though it's in the 2020 year 4 GB of RAM was considered sufficient for a budget smartphone, modern applications (especially social networks and instant messengers) are consumed in the market. 2-3 For example, a single Telegram with active chats can take up to 600-800 MB RAM, and Facebook - up 1 GB.

System system MIUI It tries to compensate for the memory deficit by aggressive caching, where unused applications are not closed completely, but are frozen in the background:

• 🐢 Slowing down switching between tasks (lags when swiping on multitasking)
• 🔄 Spontaneous reboots of applications (for example, YouTube restarts when you return to it)
• 📉 Fall. FPS In games, even on minimal graphics settings

To check the current RAM load:

1. Open Settings → About the phone → System status
2. Click on the graph Memory Use
3. If you are less than 500 MB free, this is a critical level.

⚠️ Note: Do not use Google Play memory boosters (such as Clean Master or Google Play). DU These applications not only do not help, but also increase the load on the processor, because they work in the background. MIUI The optimizer is already built in - just click Settings → Annexes → Cleanup.

2. The internal memory of the brain: when 64/128 GB is becoming scarce.

Even if you have a 128GB version of Redmi Note 9, memory is getting clogged with unnecessary files over time:

• 📁 App cache (especially Google Play Services, Chrome, TikTok)
• 🎥 Residual files after deleting applications (folders) Android/obb and Android/data)
• 📸 Photo and video duplicates (created by editing in the Xiaomi Gallery)
• 📦 APK-files of old versions of applications (remain in the Download folder)

The critical threshold for the Redmi Note 9 is when less than 10% of the total storage is free. For example, on the 64GB version, it is only 6GB of free space.

• 🐌 Slow down the recording of new files (lags when shooting videos or installing apps)
• 🔴 Fail to update the firmware (error "Insufficient memory")
• 📱 spontaneously reboot when connected to a PC

How to clean your memory correctly:

Remove the cache in Settings → Warehouse → Clear the cache

Transfer the photo/video to SD-map

Delete. APK-files from the Download folder and APK

Check the folder. Android/obb residual game files

Use the built-in storage analysis in MIUI-->

3.Outdated firmware or MIUI errors

Xiaomi regularly releases updates for the Redmi Note 9, but not all of them are optimized for hardware devices. MIUI 12 on MIUI 13 Many users cited as the reason for the increase in lags due to:

• 🐞 Bugs with animation (twitching when opening the Control Panel)
• 🔋 Increased energy consumption (background processes) MIUI eat up to 20% charge)
• 📱 Failures in the operation of sensors (incorrect operation of autorotation or approach)

How to check the relevance of the firmware:

1. Go to Settings → About the phone → System update
2. Compare the current version with the latest stable builds on the official Xiaomi website
3. If an update is available, install it, but first:

If the brakes have increased after the update, try:

• 🔄 Reverse to the previous version MIUI via Fastboot (instructions in Section 6)
• 🧹 Reset the settings to factory (but first make a backup!)
• 🛠️ Install custom recovery (TWRP) and flash optimized firmware (e.g. Xiaomi.eu)

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Before updating, disable App Auto Update in Google Play and remove unnecessary programs – this will reduce the risk of failures during the installation of a new firmware.

4.CPU overheating: why the Redmi Note 9 is "suffocating"

Helio processor G85 Redmi Note 9 is prone to overheating due to the:

• 🔥 Trottling (automatic frequency reduction when heated above 60)°C)
• 🎮 Extensive gaming sessions (especially in the PUBG Mobile or Genshin Impact)
• ☀️ Direct sunlight or use in hot climates
• 🔌 Fast charging (heating of the battery is transferred to the chipset)

How to check the temperature:

1. Install the app AIDA64 or CPU Monitor from Google Play
2. Run a performance test or just play 10 minutes of the game.
3. If the temperature is above 70°C is critical overheating!

Ways to reduce heat:

Remove the case while charging or playing

Turn off background activity in Settings → Battery. → Energy saving regime

Reduce the screen resolution to HD+ (1600×720) play

Use a cooling stand (such as Black Shark Cooler)

Update the heat paste (requires disassembly of the device)-->

⚠️ Warning: If the phone is heated even in a simple (for example, when watching YouTube), this may indicate a malfunction of the battery or detachment of the heat pad between the processor and the housing, in which case only a replacement of the battery or re-sticking the thermal interface in the service center will help.

5. Application background activity and autoboot

One of the most insidious causes of brakes is the hidden activity of applications that run automatically and consume resources. MIUI There's a built-in startup manager, but it doesn't always block all unnecessary processes»:

• 📱 Facebook, Instagram, TikTok (constantly sync data)
• 📊 Google Play Services (can take up to 30 hours% CPU background)
• 🔍 Antivirus applications (e.g. Avast or 360 Security)
• 🎵 Music streaming services (cache songs in the background)

How to turn off autoboot:

1. Go to Settings → Applications → Application Management
2. Select an app (such as Facebook) → Auto-start → Shut down.
3. System applications (e.g. Mi Video) may require permission to change system settings (given through the use of the system). ADB)

For complete control of background activity:

• 🛡️ Use Greenify (requires root for full functionality)
• 📵 Disable Background Data Update for Unnecessary Applications in Settings → The Internet and the Internet → Transfer of data
• 🔄 Check the Settings section regularly → Battery. → Using a battery for suspicious activity

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Even after you turn off the autoboot, some apps (such as instant messengers) will start when you receive push notifications. To completely block their background work, you need to turn off notifications in the application settings.

6.Reset to factory settings: when it really helps

If all previous methods failed, the last chance to bring the Redmi Note 9 back to life is a full hard reset.

• 🗃️ All user data (photos, videos, contacts)
• 📱 Installed applications and their settings
• 🔧 System settings (Wi-Fi, Bluetooth, fingerprints)
• 🔄 Updates to the firmware (return to the factory version) MIUI)

How to do the reset correctly:

1. Create a backup: Settings → System and device → Backup → Create a backup (Select Local Storage or Xiaomi Cloud)
2. Perform reset: Settings → The phone. → Resetting settings → Delete all data (you will need to enter a pattern lock or PIN-code)
3. After reset: Don’t restore data from the backup right away – first check the phone’s “clean” state Install apps selectively, not all at once Disable app auto-update on Google Play

⚠️ Note: If the brakes are left after reset, this may indicate a hardware problem: - Wear of flash memory (eMMC) - Memory malfunction - Damage to the motherboard (for example, after a fall) In this case, only diagnostics in the service center will help.

For power users, if the reset didn't work, try flashing custom firmware (like LineageOS or Pixel Experience).

• 🔓 Unlock the bootloader (fastboot oem unlock)
• 📥 Installations TWRP Recovery
• 🛠️ Firmware through ADB Sideload or TWRP

7. Hardware problems: when the "iron" is to blame

If software methods didn't work, the brakes could be due to the physical wear and tear of the components. 9 after 2-3 years:

How to check the status of the battery:

1. Install AccuBattery from Google Play
2. Charge your phone to 100% and discharge to 0% without charging.
3. Check the battery health setting: 🟢 90-100% — battery in good condition 🟡 80-90% — Significantly reduced capacity (replacement is recommended) 🔴 Below. 80% — critical condition (the battery is swelling and heating up)

If you suspect a flash memory malfunction, run the test:

adb shell


su




dd if=/dev/zero of=/storage/emulated/0/testfile bs=1M count=1024

If the command is executed for more than 30 seconds or if it makes errors, the memory is worn out.

8. MIUI Optimization: Hidden Settings for Acceleration

MIUI It has many hidden features that you can use to speed up the Redmi Note 9:

• 🚀 Disabling animation: Settings → Additionally. → Special facilities → Remove animation (set the animation scale to 0.5x or shut it down completely)
• 📱 Activation of the performance mode: Settings → Battery. → Performance mode (Includes maximum processor frequencies but reduces running time)
• 🔄 Limitation of background processes: Settings → Developer → Process limit (set the process limit) 2-3) (Requires the enabler of the Developer Mode – click 7 once-on MIUI phone)
• 🗑️ Cleaning Dalvik cache (requires) TWRP): Reboot to Recovery → Advanced → Wipe Dalvik Cache

For experienced users: you can disable unnecessary system services MIUI through ADB:

adb shell


pm uninstall -k --user 0 com.miui.analytics




pm uninstall -k --user 0 com.xiaomi.ab




pm disable-user --user 0 com.miui.cleanmaster

This will turn off analytics collection, advertising services and the built-in cleaner.

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Do not disable system applications at random - this can cause the failure of key functions (for example, the camera or mobile network). TWRP!

FAQ: Frequent questions about the Redmi Note 9 brakes