How to speed up Xiaomi Redmi Note 9T: a complete guide to optimization

Xiaomi Redmi Note 9T with MediaTek Dimensity 800U processor and 4/6 GB of RAM initially demonstrates excellent performance. But over time, even this smartphone begins to “brake”: applications open for a long time, animations twitch, and the battery dies in half a day. The reasons can be different from an overloaded system to outdated firmware. In this article, we will discuss specific acceleration methods that work on MIUI 12/13/14 without losing warranty or risk of “bricking” the device.

It's important to understand that not all lags are hardware-related. Software optimization is more often to blame: background processes, cache debris, incorrect energy saving settings, or even viruses. We tested each method on a real Redmi Note 9T (model M2007J22G) and selected only those that give a noticeable increase in speed. If after all the manipulations the brakes are left, perhaps the problem is the physical wear of the drive (see section on diagnostics).

1. Cleaning the system: remove garbage and cache

The first thing you need to do is to free up memory and reset the app cache. On the Redmi Note 9T with 64/128 GB of storage, free space directly affects the read/write speed, and if the memory is less than 10%, the system starts to “glut”.

Start with the built-in Cleanup tool:

• 📱 Open the Settings. → The phone. → Memory (or Settings) → Annexes → Cleaning in new versions MIUI).
• 🧹 Click “Clean” – this will delete temporary files, remnants of remote applications and cache of system processes.
• 🗑️ Go to the “Deep Cleanup” tab and select “Unnecessary Files” (here often accumulate gigabytes of garbage from instant messengers and social networks).

For advanced cleaning, use manual cache reset of individual applications:

1. Go to Settings → Applications → Application Management.
2. Choose the “heaviest” app (like Facebook, Instagram, or TikTok).
3. Click on Storage → Clear cache (do not delete data, otherwise you will log out of your account!).

⚠️ Note: Do not clear the cache of system applications like com.miui.home or android.process.media – this can cause malfunctions. MIUI.

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If the app is slower after cleaning the cache, just restart the smartphone. The system will restore the necessary temporary files automatically.

2. Optimization of background processes and autoboot

MIUI is known for aggressive memory management, but sometimes it oversteps the stick by shutting down processes or allowing the background to overload the system. On the Redmi Note 9T, this manifests itself as a hangover when switching between applications.

To limit background activity:

• ⚙️ Go to Settings. → Battery and productivity → Battery management.
• 🔄 Select “App Select” and tick “Limit background activity” for unnecessary applications (such as games or rarely used utilities).
• 🚫 In the AutoRun section, turn off autoboot for apps that shouldn’t work in the background (save messengers!).

For advanced users, there is a hidden heap size setting that affects multitasking:

adb shell settings put global settings_enable_freeform_support 1


adb shell am broadcast -a android.intent.action.CLOSE_SYSTEM_DIALOGS

These commands (enter via ADB) increase the limit of background processes, but can reduce battery life.

3. Update firmware and reset settings

The slowdown is often due to an outdated version of MIUI. Xiaomi regularly releases patches that optimize performance for MediaTek Dimensity 800U. Check the relevance of the firmware:

• 🔄 Go to Settings. → The phone. → Updating the system.
• 📥 If you have an update, download it (preferably via Wi-Fi) and install it.
• 🔋 Make sure the battery is over 50% or the process will stop.

If the updates didn’t help, try a soft reset (without data loss):

1. Go to Settings → About the phone → Reset settings.
2. Select Reset All Settings (this won’t delete files, but will return system settings to factory settings).
3. After the reboot, reset the smartphone by disabling unnecessary features (such as MIUI animation).

⚠️ Note: If after the update, the smartphone began to work even worse - perhaps the new firmware contains bugs. In this case, roll back to the previous version via Fastboot (instructions on the official forum Xiaomi).

4. Disable animation and visual effects

MIUI is famous for its “beauties”, but animations and transitions eat up the resources of the processor. On the Redmi Note 9T with a 90 Hz screen, this is especially noticeable: the system tries to maintain a high frame rate, but “sinks” on the weak cores of the Dimensity 800U.

To speed up the interface:

• 🎨 Open the Settings. → Display. → Screen refresh rate and select 60Hz (this will reduce the load on the screen) GPU).
• 🖥️ Enable the "Light" mode in Settings → Special facilities → Simplified mode (removes unnecessary effects).
• 🛠️ To completely disable animation, activate the developer mode:

1. Go to Settings. → About the phone and 7 times tap on the "Version" MIUI».
2. Return to Settings, open Advanced Settings → For Developers.
3. Find the items: Window animation scale → Disable the animation scale of the transition → Disable the animation duration of animation → Disable

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Disabling animations gives you a speed increase of up to 15-20% when switching between applications, but makes the interface less “live”.

5. Storage optimization: data portability and formatting

The UFS 2.1 drive in the Redmi Note 9T gets fragmented over time, especially if you install/delete applications frequently, which leads to "hangs" when you read files.

Method 1: Transfer applications to a memory card

• 📁 Insert microSD (class recommended) A2 or UHS-I).
• 🔄 Go to Settings. → Annexes → Application management.
• 📱 Select the application → «Warehouse» → «Change» → «Memory map».

Important: Not all applications support portability. System utilities and secure games (such as PUBG Mobile) cannot be ported.

Method 2: Formatting the drive

If your smartphone is slowing down even after cleaning, try formatting your internal memory (all data will be deleted!):

1. Make a backup through Settings → About Phone → Backup.
2. Go to Settings → About Phone → Resetting → Delete all data.
3. After resetting, restore only the necessary data (do not restore the app cache!).

6.Verification for viruses and malware

Viruses and mining bots are a common cause of sudden brakes, loading the processor in the background, causing overheating and performance to decline. On the Redmi Note 9T, this manifests itself as:

• 🔥 Overheating even in plain.
• 📉 Quick discharge of the battery (for example, during the night sits on the 30-40%).
• 🚀 Constant loading CPU (checks in the settings → The phone. → Status of the system).

How to check and remove viruses:

1. Install Malwarebytes or Dr.Web Light from Google Play.
2. Run a full scan (may take 10-15 minutes).
3. Remove all threats and reboot your smartphone.

If the antivirus has not found anything, but suspicions remain:

• 🛡️ Check the list of installed applications in Settings → Applications for suspicious programs (for example, with names like com.system.update or android.engine).
• 🔍 Open the Settings. → Battery and productivity → Battery usage and see which applications consume the most energy.

Check the CPU boot in Task Manager

Scan Malwarebytes

Remove unfamiliar applications

Disable the installation from unknown sources-->

7. Alternative firmware and custom cores

If all of these methods don't work, the radical solution is to install custom firmware, and that will remove the unnecessary services. MIUI And add optimizations for Dimensity. 800U. Popular options for Redmi Note 9T:

• 📱 Pixel Experience – pure Android without shell MIUI.
• ⚡ LineageOS - stable firmware with minimalist interface.
• 🔥 Xiaomi.eu – modified MIUI Advertising-free and Chinese-based.

⚠️ Warnings before firmware:

• 🔓 Unlocking the bootloader will reset all data and void the warranty.
• 🔧 You need to know how to work with Fastboot and TWRP.
• ⚠️ The wrong firmware can “brick” the device (turn into a “brick»).

If you decide, follow the official guides on the XDA Developers or 4PDA forum. For the Redmi Note 9T, the current instructions are:

• Pixel Experience for Redmi Note 9T
• Xiaomi.eu (MIUI without bloat)

8. Hardware problems: when it's time to get into service

If none of the software methods worked, the cause of the brakes could be hardware. The Redmi Note 9T has typical "iron" problems:

• 🔋 Battery wear – when the battery is degraded below 70% of capacity, the smartphone begins to troll (limit performance). → Battery → Battery status or AccuBattery application.
• 💾 The wear of flash memory - after 300-500 Write/Delete cycles, the reading speed drops in 2-3 Diagnosed via AndroBench (reading speed below) 200 MB/s - critical).
• 🔥 Overheating of the processor - if Dimensity 800U heats up above 60°C, it automatically lowers the frequencies. Causes: dried thermal paste, connector contamination, or radiator damage.

The cost of repair in the official service Xiaomi (for 2026):

⚠️ Note: If the smartphone is warranty (up to 2 years from the date of purchase), do not open it yourself - this will cancel the warranty obligations.

FAQ: Frequent questions about the Redmi Note 9T acceleration