How to speed up Xiaomi Mi 9: from software optimization to hardware upgrades

Xiaomi Mi 9 is still one of the most popular flagships of the brand, but over the years even top-end hardware begins to slow down. If your smartphone has become slower to respond to touch, applications are loaded for a long time, and animations twitch — do not rush to write it off. In 90% of cases, the problem can be solved without replacing the device.

This article is not about shamanism with “magic” applications for acceleration (most of them are dummy), but about system solutions: from basic cleaning to deep optimization. MIUI We tested all the methods on the Mi 9 with firmware from the MIUI 12 to MIUI 14, as well as on custom builds such as Pixel Experience.

Important: some methods require unlocking the bootloader or root rights, which cancels the warranty and can lead to a device "brick", and you perform all the manipulations at your own risk.

1.Diagnostics: Why is Xiaomi Mi 9 slowing down?

Before you optimize, you need to understand the root of the problem: the Mi 9 on the Snapdragon 855 should not be “lagging” in everyday tasks even after 5 years – if this happens, one of three is to blame:

• 📱 Software junk: clogged cache, background processes, viruses or crookedly optimized software.
• 🔋 Hardware wear: degraded battery (less than 80% capacity) or overheating chipset.
• 🤖 Firmware: an outdated version MIUI, «Custom build curve or core conflict with applications.

To identify the bottleneck, use the built-in tools:

1. Open Settings → About Phone → MIUI version and tap 7 times on the build number to activate Developer Mode.
2. Return to Settings → Additional → For developers and turn on CPU statistics.
3. Run a heavy app (like Genshin Impact) and watch the download schedule. CPU/GPU real-time.

If the CPU load jumps to 100% on simple tasks (scrolling Instagram) and the temperature exceeds 50°C is a problem in the heat paste or firmware. If the lags are accompanied by a sharp drop in charge, it's the battery's fault.

2. Basic optimization: cleaning without root

Start with simple steps that don’t require deep knowledge and don’t carry risks, and these methods will work even if you’ve never delved into Xiaomi’s settings.

Cleaning up cache and garbage

MIUI It's known for aggressively cacheting data, but not always cleaning it properly, and as a result, after a year of use, it accumulates in memory to the point where it's not used. 3-5 GB of unnecessary files.

• 🧹 Cleaning the application cache: Settings → Annexes → Select an application → Warehouse → Clear the cache. Pay particular attention to Facebook, Instagram and Google Play Services, which are the most common memory clogs.
• 🗑️ Remove unnecessary files: Use the built-in Cleanup app (Security) → Deep cleaning. Remove. APK-files, downloads and duplicate photos.
• 🔄 Resetting settings MIUI: Settings → The phone. → Resetting (not to be confused with a full reset!) will return default settings to launcher, animations and background processes.

After cleaning, restart the phone is a must-do step, as many processes are involved. MIUI They will only be restarted after rebooting.

Disabling background processes

MIUI It's the default that allows apps to run in the background, even if you're not using them. RAM processor time.

1. Go to Settings → Battery and Performance → Battery Management.
2. Select Applications and for any unnecessary (for example, LinkedIn, TikTok) set a Background activity restriction → Limit.
3. In the same menu, turn off AutoRun for applications that should not start when the system starts.

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If notifications stop coming after the background processes are turned off (for example, from Telegram), add the application to the Battery Exclusions in the same menu.

Firmware update

Xiaomi regularly releases patches to optimize performance. MIUI 14 added memory compression that reduces lags when multitasking.

• 📲 Check the relevance of the firmware: Settings → The phone. → Updating the system.
• 🔍 If you don’t have an update, your version is older. MIUI 13, try the manual firmware through the Mi Flash Tool (instructions in the section about firmware).

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Update through OTA (Airborne) is safer, but handheld firmware often gives you better optimization, especially if your region is not a priority for Xiaomi.

3. Advanced optimization: setting up MIUI speed

If the basic methods didn't work, it's time to dig deeper, and these methods will take longer, but they will give you a noticeable increase in productivity.

Disabling animations and visual effects

MIUI They're known for their beauty, but they eat up resources. Turning off animations will speed up the opening of apps and switching between tasks.

1. Activate Developer Mode (as in the first section).
2. Go to Settings. → Additionally. → For developers and find:

Download animations

Smooth crossings

Once the animations are turned off, the smartphone will respond to touch instantly, but the interface will become less lively.This method is especially useful for gamers, where every millisecond counts.

Optimization MIUI assisted ADB

Android Debug Bridge via Android (ADB) You can disable unnecessary system processes that slow down the Mi 9, such as Xiaomi Cloud or other services. MSA (plug-in).

You'll need:

• 🖥️ Computer with installed ADB Tools.
• 📱 Included Debugging by USB on the phone (Settings) → For developers).

Connect your phone to your PC and execute commands in cmd:

adb shell


pm uninstall -k --user 0 com.miui.cloudservice # Disconnects Xiaomi Cloud




pm uninstall -k --user 0 com.xiaomi.midrop # Disable Mi Drop




pm uninstall -k --user 0 com.miui.analytics # Disables Analytics Gathering




pm uninstall -k --user 0 com.miui.systemAdSolution # Disables the MSA Ad Module

These commands will not remove the apps completely, but only disable them for the current user. To get it back, use:

cmd package install-existing com.miui.cloudservice

Install ADB Tools on PC

Enable debugging over USB on your phone

Connect your phone over cable (not Wi-Fi!)

Check the connection with the adb device command

Backup important data-->

Changing the launcher to an easy analog

Standard launcher MIUI (POCO Launcher or Mi Home: Consumes up to 300-500 MB RAM Alternatives like Nova Launcher or Lawnchair work in the 2-3 more effectively.

Selection recommendations:

After installing the new launcher:

1. Open its settings and turn off all animations.
2. Set the number of columns/lines to a maximum (e.g, 5×6) — It'll reduce scrolling.
3. Turn off Google Discover (if any) – it constantly loads data in the background.

4. Firmware and custom ROM: radicalization

If the Mi 9 is slowing down even after all the optimizations, it's time to think about changing the firmware. MIUI Over time, it swells from unnecessary features, and custom builds (for example, LineageOS or Pixel Experience) offer “clean” Android without excess software.

Advantages of custom firmware:

• ⚡ High speed: lack of background processes MIUI increases 15-30% benchmark.
• 🆕 Updates: even on the old Mi 9 you can put Android 14.
• 🔒 Without advertising and spyware modules: no MSA, Xiaomi Cloud and other Bloatware.

Cons:

• ⚠️ Requires unlocking the bootloader (resets all data!).
• 🔧 Maybe it won't work. NFC, IR-blaster or wide-angle camera (depending on build).
• 🔋 Possible problems with autonomy (some cores are poorly optimized).

How to flash custom firmware on Xiaomi Mi 9

Instructions for Pixel Experience (Android 13):

1. Unlock the bootloader: Connect your Mi Account to your phone. Go to Xiaomi's official website and request unlock. Download Mi Unlock Tool, connect your phone to Fastboot (press Power). + Vol-) and follow the instructions.

Install. TWRP

fastboot flash recovery twrp-3.7.0_9-0-cepheus.img


fastboot boot twrp-3.7.0_9-0-cepheus.img

Flush the firmware.

• Download Pixel Experience for cepheus (codename Mi 9) from the official website.
• In TWRP, run Wipe → Advanced Wipe (mark Dalvik, Cache, System, Data).
• Install. ZIP-Firmware and GApps (if you need Google services).

Recommended firmware for Xiaomi Mi 9 (2026):

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If you are a beginner, start with MIUI EU — It's a modified official firmware without ads or apps, and it's more stable than custom software. ROM and retains all functions including NFC and IR-blaster).

5 Hardware modifications: when software does not help

If the software is exhausted and the Mi 9 is still slowing down, the problem can be in the hardware.

• 🔋 Battery degradation (capacity below 80% → The phone starts to trattle the processor).
• 🌡️ Overheating (dried thermopaste or dust-clogged board).
• 💾 Flash memory wear (slow recording/reading data).

Battery replacement

Mi battery 9 (model BM4B) lose 20-30% capacity 2-3 year of active use, when the charge drops below 80%, The system automatically limits performance to save energy.

Signs of a worn-out battery:

• The phone turns off when 20-30% charge.
• It heats up quickly even on simple tasks.
• AccuBattery shows a capacity of less than 3000 mAh (original - 3300 mAh).

Decisions:

1. Calibration (if the problem is in the software): Discharge the phone to 0% (Charge until it's off. 100% without interruption (use the original power supply). 2-3 once.

Battery replacement

• Cost: 1500-3000 ₽ (depending on the workshop).
• Recommended battery: original BM4B silden.
• After the replacement, perform Wipe Battery Stats in the TWRP (if established).

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Before replacing the battery, check its real capacity in the AccuBattery application (after the battery is replaced). 5-10 Charging cycles if higher 3000 mAh, the problem may not be in the battery, but in the firmware or background processes.

Replacement of thermopaste

Snapdragon 855 It is prone to overheating, and through 3-4 The thermopaste on the chip dries out, and this leads to trottling and lagams.

How to check for overheating:

• Install. CPU Monitor or DevCheck.
• Launch it. 3D Mark or Geekbench.
• If the temperature is greater than 75°C, and the processor frequency falls below 2.0 GHz - it's time to change the thermal paste.

Replacement process:

1. Disassemble the phone (needs a suction cup, plastic spatula and screwdriver). T3).
2. Remove the motherboard and clean the old paste with alcohol.
3. Apply a new thermal paste (Arctic) MX-6 noctua NT-H2) thin-layer.
4. Collect your phone and check the temperature under load.

Attention! ⚠️ Disassembly Xiaomi Mi 9 requires experience — boards are attached to latches that are easy to break. If you are not sure of their abilities, contact the service center.

Increase memory with microSD (root only)

If you have a Mi 9 at 64GB, over time, the memory gets clogged and the system doesn't have enough cache space. The solution is to mount the microSD as internal storage (Adoptable Storage feature).

Requirements:

• 📁 Memory map UHS-I (class A2 or higher, for example, Samsung EVO Plus).
• 🔓 Root-rights (or custom core with support for Adoptable Storage).

Instructions:

1. Insert microSD into your phone.
2. Format it as internal memory in Settings → Storage.
3. Install. App2SD or Link2SD and move the apps to the map.

Attention! ⚠️ Once formatted as internal memory, the card cannot be used in other devices without being cleaned, and microSD applications will run slower than internal memory (especially if the card is cheap).

Overclocking and undervoltage: for power users

If you're willing to take risks, you can try overclocking the processor or lowering the voltage to reduce the heat, which requires an unlocked bootloader and root.

Overclocking of the CPU/GPU

The Snapdragon 855 in the Mi 9 has a margin in frequencies, but overclocking can lead to:

• ⚡ Increased energy consumption (the battery will sit on the 30-50% faster).
• 🔥 Overheating (the risk of trottling or even turning off your phone).
• 💥 Loss of stability (app departures, artifacts in games).

If you're willing to experiment:

1. Install a kernel with overclocking support (e.g. FrancoKernel or KirinKernel).
2. Download Kernel Adiutor or EX Kernel Manager.
3. In the section CPU Increase the maximum frequency of the cores: Larger cores (Cortex-A76): up to 2.96 GHz (stack 2.84 GHz) Small cores (Cortex-A55): up to 1.9 GHz (stock - 1.8 GHz).

Adreno 640

675 MHz

585 MHz

After overclocking, be sure to test stability in Geekbench or 3DMark. If the phone overheats or flies - return stock frequencies.

Undervoltage (reducing voltage)

This method reduces the voltage on the processor, reducing heating and power consumption without losing performance. - For Snapdragon 855 You can save up 10-15% battery.

Instructions:

1. Install. EX Kernel Manager.
2. Go to section. CPU Voltage.
3. For each core, lower the voltage by 25-50 mV (e.g. with 950 μ 900 m).
4. Save the settings and check for stability in PCMark.

FAQ: Frequent questions about speeding up Xiaomi Mi 9