How to speed up Xiaomi Mi 9: from cache cleaning to deep MIUI optimization

Xiaomi Mi 9

Snapdragon 855

The reason is not because of the “aging” of iron

MIUI

In this article, 12 proven ways to speed up the Xiaomi Mi 9, from basic (cache cleaning) to advanced (disable system services via ADB). All methods are tested on current versions of MIUI 14 and HyperOS, work without root rights and do not require complex manipulations. If your smartphone “choked” after the update or simply lost its former agility, follow the instructions in order.

⚠️ Note: Before any changes to the system, back up your data through Settings → The phone. → Backup: Some methods (e.g., resetting the Dalvik partition cache) can cause a smartphone to temporarily unusable.

1.Cache and garbage cleanup: the first step to speeding up

The most obvious but often overlooked cause of brakes is clogged app cache and system debris. MIUI actively caches data to speed up program re-runs, but over time this cache grows to gigabytes and begins to interfere.

Start with manual cleaning:

1. Go to Settings → Applications → Application Management.
2. Sort the list by cache size (click on the three dots in the top right corner).
3. Select applications with a cache of more than 500 MB (most often these are social networks, messengers, browsers) and click Clear cache.

For deep cleaning, use the built-in “Security” application:

• 🧹 Acceleration: Run the check in Acceleration - the system will close the background processes and free RAM.
• 🗑️ Clean up garbage: In the Deep Cleanup section, delete temporary files, remnants of deleted applications and duplicates.
• 📱 Auto Clean: Activate Cleanup when locking the screen in the app settings.

⚠️ Note: Do not clean the cache of system applications like com.android.systemui or com.miui.home manually – this can cause shell malfunctions. MIUI.

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If the app is slower after cleaning the cache, don't worry. It's temporary: the data is cached again the next time it runs, but without digital ballast.

2. Disable animation and visual effects

MIUI is known for its heavy animations that eat up CPU and RAM resources, and turning off or reducing these effects will make the interface visually less smooth, but will significantly speed up the system’s response.

Method 1: Developer Settings

1. Activate Developer Mode: Go to Settings → About Phone and click on MIUI Version 7 times.
2. Go back to the main settings menu and find a new section for developers.
3. Scroll to the Drawing block and set: Window animation scale → No animation transition scale → No animation transition scale → No animation animation animation animation duration → 0.5x (or turn off completely)

Method 2: Lightweight MIUI Lite mode

If your Xiaomi Mi 9 is running MIUI 12.5+ or HyperOS, activate the lightweight mode:

1. Go to Settings → Special Opportunities → Lightweight Mode.
2. Turn on the option and restart the smartphone.

This will disable some of the visuals and simplify the interface, but some features (like Always-on Display) will become unavailable.

3. Optimization of application background activity

One of the main bottlenecks of MIUI is aggressive background control, on the one hand, the system kills unnecessary tasks to save battery, on the other hand, some applications (messengers, mail) must work in the background, otherwise you will not receive notifications on time.

How to set the balance:

• 🔄 Turn off Autostart: Go to Settings → Annexes → Application management → Autoplay and deactivate autoboot for unnecessary programs (games, rarely used utilities).
• 📵 Limit background activity: In the same application management menu, select Background Activity and set the Restricted mode for most applications.
• ⚡ Exceptions for important applications: For instant messengers (Telegram, WhatsApp) and mail, install No restrictions.

For advanced users: disabling MIUI Optimization via ADB

This option removes some of the MIUI limitations on background processes, but can increase battery consumption.

adb shell settings put global hidden_api_policy 1

Then reboot your smartphone. To get it back, use:

adb shell settings delete global hidden_api_policy

🔹 Check Auto-Run Applications

🔹 Limit background activity for games and utilities

🔹 Add messengers to exceptions

🔹 Reboot the smartphone after the changes-->

4. Resetting the Dalvik/ART section cache

Dalvik cache (or ART in newer versions of Android) stores optimized versions of installed applications. Over time, it fragments, which leads to slowdown of programs and increased RAM consumption. Cleaning this cache does not delete user data, but requires a reboot.

How to Reset Dalvik-Cache:

1. Turn off your smartphone.
2. Press the Power button + Volume up to enter Recovery.
3. Select Wipe & Reset → Wipe Cache (use volume buttons for navigation, power button for confirmation).
4. After cleaning, restart the device (Reboot → System).

⚠️ Note: The first download after Dalvik reset will take up to 5-10 It's okay. Don't interrupt the process, even if the screen stays black for a long time.

After this procedure, the applications will start slower the first time, but then their work stabilizes.The effect is noticeable on “cluttered” smartphones with 50+ installed programs.

5. Update of firmware and core

The Xiaomi Mi 9 slowdown is often due to outdated firmware or an unoptimized kernel.The manufacturer regularly releases bug fixes and performance improvements, but many users ignore them.

How to update correctly:

• 📲 Through OTA: Go to Settings. → The phone. → Update the system and check for updates. Install the latest stable version MIUI or hyperos.
• 🔧 Hand-held firmware: If OTA does not offer a fresh version, download the full firmware package from the official Xiaomi website and install via Recovery.
• 🔄 Reset after update: If after the update the smartphone began to work worse, reset settings (Settings) → Additionally. → Resetting settings, but don’t format internal memory.

For enthusiasts, custom cores like FrancoKernel or Kirisakura can deliver up to 20 percent performance gains, but require unlocked bootloader and root rights. Install them only if you understand the risks!

Storage optimization: from formatting to replacing with UFS 3.0

Over time, the Xiaomi Mi 9 file system gets fragmented, especially if you frequently uninstall and install apps, which causes a slowdown in read/write, even on fast UFS 2.1 memory.

Ways to optimize storage:

• 📁 Formatting: Back up data and complete formatting with Recovery (Wipe & Reset) → Wipe All Data. This will reset the file system to a factory state.
• 🔄 App portability: Move heavy games (such as Genshin Impact or Call of Duty Mobile) to a memory card (if supported) or use Settings → Annexes → Move it to SD.
• 🛠️ Replacement UFS 3.0: Service centers offer upgrades to storage UFS 3.0 (for example, from 128 GB to 256 GB) This will increase the read speed to 2100 MB / s (versus 900 MB / s in the standard version). UFS 2.1).

⚠️ Note: Formatting will delete all data, including photos in the folder DCIM Use Google Photos or Mi Cloud to back up your files.

To check the storage speed, use the A1 SD Bench application. Normal readings for Mi 9:

• Reading: 800-950MB/s
• Recording: 250-350MB/s

If the values are lower by 30% or more, it is time to optimize the storage.

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Formatting is a last resort, and before doing so, try clearing the cache and removing unnecessary files, and the effect of formatting is only noticeable when fragmentation is severe (usually after 1.5-2 years of use).

7. Alternative launchers and shells

The standard MIUI launcher (com.miui.home) consumes up to 300-400MB of RAM and sometimes slows down when scrolling desktops, replacing it with a lightweight alternative can speed up navigation.

The best launchers for Xiaomi Mi 9:

How to install an alternative launcher:

1. Download APK from the official website (for example, Nova Launcher).
2. Install the file and select the new launcher as the main one in the settings (Settings → Applications → Default → Launcher).
3. Customize gestures, animations and desktop markup to your needs.

⚠️ Attention: Some functions MIUI (For example, Always-on Display or Game Turbo may not work properly with third-party launchers, 4PDA or XDA Developers).

8. Radical-methods: reset to factory settings and custom firmware

If all previous methods failed, radical measures remain: a complete reset or custom firmware installation, which will return the Xiaomi Mi 9 to the “factory” state or even surpass it.

Reset to factory settings:

Deletes all data, including accounts, photos and apps, and only use it if other methods have failed.

1. Back up via Settings → About Phone → Backup or Mi Cloud.
2. Go to Settings → Additional → Resetting settings.
3. Choose to erase all data and confirm the action.
4. After the reboot, set up your smartphone as new.

Castom firmware:

Firmware like LineageOS, Pixel Experience or crDroid lacks the heavy MIUI shell and offers a cleaner Android, but they will require:

• 🔓 Open the bootloader (fastboot oem unlock).
• 📥 Install custom recovery (TWRP Or OrangeFox).
• 🛠️ Sweep ZIP-Firmware and GApps (if you need Google services).

⚠️ Attention: Installing custom firmware voids warranty and can lead to a device "brick" if you make an error. Use only verified forum builds XDA Developers or 4PDA.

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Factory reset helps in 90% of cases of strong brakes, but requires re-tuning the smartphone. Custom firmware gives performance gains of up to 25-30%, but is only suitable for advanced users.

FAQ: Frequent questions about the acceleration of Xiaomi Mi 9