Why Xiaomi Redmi 9 is slowing down: a full analysis of the causes and working methods of elimination

Xiaomi Redmi 9 is one of the most popular budget smartphones, but even it is not immune to performance problems. If your device starts to stutter when scrolling menus, open apps for a long time or suddenly “freeze” during games, this does not always mean that it is time to buy a new phone. 80% of the time the brakes are caused by software factors that can be eliminated on their own without going to the service center.

This article will help you understand why Redmi 9 is slowing down in your case: we will analyze both obvious causes (filled memory, background processes) and hidden ones (firmware errors, battery wear). For each problem, we will provide step-by-step solutions with illustrations from the real MIUI interface, as well as tips for prevention.

1. RAM overload: the main cause of lags

Redmi 9 is equipped with only 3-4 GB of RAM (depending on the modification), and this is enough only for basic tasks. Modern applications (especially social networks and instant messengers) “eat” memory even in the background. When RAM is full, the system starts using the paging file on slow internal memory — hence the brakes.

How to check the loading of RAM:

1. Open Settings → About the phone → System status.
2. Slip on Memory (or Use RAM in newer versions of MIUI).
3. If less than 500 MB is free, it’s time to clean.

• 🧹 Close the background apps: swipe up the screen and swipe off all unnecessary cards (in) MIUI It's called "Recent" and it's important that you don't use the Play Market "task killers" -- they only make things worse by making the system constantly restart processes.
• ⚙️ Limit background activity: in Settings → Annexes → App management select a problem app (such as Facebook or TikTok) and turn off AutoRun option.
• 🔄 Reboot your phone: This clears the RAM cache. Do this once every 2-3 days.

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If your phone is still slowing after cleaning your RAM, check Settings → Special Features → Accelerator. Turn on the option Memory Optimization, which automatically closes unnecessary processes.

2. filled storage: when less than 10% of memory remains

Redmi 9 comes with 32/64/128 GB of internal memory, but is actually available to the user 5-10 GB less due to preinstalled software. When less than 10% of free space remains, the system begins to crash: applications open for a long time, photos are not saved, and MIUI updates refuse to install.

How to make room:

1. Delete the app cache: Settings → Storage → Clear the cache (you can do it for all apps at once).
2. Move your files to a memory card or cloud (such as Google Photos or Mi Cloud).
3. Remove duplicate photos/video with apps like Files by Google.

⚠️ Note: Do not delete the Android folder manually - this can break the application. To clean system files, use only built-in tools MIUI.

3.Outdated firmware or MIUI errors

Xiaomi regularly releases updates for Redmi 9, but many users ignore them. Meanwhile, new versions of MIUI include performance optimizations, bug fixes and security patches. If your phone brakes after the update, it may be that the firmware is crooked or conflicting with user settings.

How to update the firmware correctly:

1. Connect to stable Wi-Fi (not mobile internet!)
2. Go to Settings → About the phone → System update.
3. If the upgrade weighs more than 1GB, make room in advance.
4. Once installed, restart the phone manually (without waiting for an automatic reboot).

• 🔧 Resetting: If the lags appeared after the update, try resetting to factory settings (Settings) → Additionally. → Recovery and reset. Important: backup your data!
• 📥 Hand-held firmware: if OTA-Update does not help, download the full firmware package from the official Xiaomi website and install through System Update → Three points. → Select a firmware file.

4.Overheating: Why the phone "dulls" when loaded

The Redmi 9 is built on a MediaTek Helio G80 processor that is prone to overheating under prolonged loads. When the chip temperature exceeds 60°C, the system automatically trottlits performance (reduces the processor frequency) to prevent damage, resulting in the phone slowing down, games lag, and the camera refuses to turn on.

Causes of overheating:

• 🔥 Games or videos in 4K: processor and graphics accelerator are working at the limit.
• ☀️ Direct sunlight: even in standby mode, the phone can heat up to 50°C.
• 🔋 Charging. + Playing at the same time: This is the most dangerous combination for the battery and the processor.
• 🧊 Clogged radiator: dust in the charging connector or under the lid can block the heat sink.

How to cool your phone:

1. Remove the case (especially silicone – it retains heat).
2. Close all apps and let the phone rest for 10-15 minutes.
3. If overheating occurs during charging, use the original power supply (not fast charging!).
4. For games, set the FPS limit: in Settings → Special Features → Accelerator → Game settings, select 60 FPS instead of Auto.

5. Viruses and malware: hidden "brakemakers"

Even if you haven’t installed suspicious APKs, viruses can get in through:

• 📎 Investments in SMS/messengers (for example, "you have a parcel, download the file»).
• 🎮 Pirate games or modified applications (e.g. Spotify Premium or Spotify Premium) PUBG Mobile with cheats).
• 🔗 Fake websites offering to “speed up the phone” or “clear the cache».

Signs of infection:

• The phone slows down even after resetting.
• Unknown apps appear in the menu (e.g. com.android.system.update).
• The battery is discharged in 2-3 hours without active use.
• Mobile traffic is consumed in the background (check in Settings) → SIM-maps and mobile networks → Traffic).

How to remove viruses:

1. Install Malwarebytes or Dr.Web Light from Google Play.
2. Start a deep scan (not fast!).
3. If the antivirus does not find threats, but suspicions remain - reset to factory settings and do not restore data from the backup (the virus can be saved in the backup).

⚠️ Note: Some “optimizers” from the Play Market (e.g. Clean Master or the Play Market) DU Speed Boosters contain advertising software themselves and can aggravate the brakes. Use only official tools. MIUI or proven antiviruses.

6. Battery wear: how the battery affects performance

After 300 to 500 charging cycles (approximately 1.5 to 2 years of active use), the Redmi 9 battery capacity drops to 70 to 80 percent of the original battery, and the worn battery not only discharges faster, but also causes voltage drawdowns, which causes the processor to run unstable, and this manifests itself as:

• Suddenly hanging when opening applications.
• Spontaneous reboots at a charge level below 30%.
• Brakes when the camera and GPS work simultaneously (for example, in Google Maps).

How to check the wear of the battery:

1. Enter the code in the phone app: ##4636##.
2. Select Battery Information and see the Wear Level (or Battery Health) option.
3. If the value is above 20%, it is time to change the battery.

What to do:

• 🔋 Replace the battery at the service center (cost about 1500-2500 rubles). Don't buy cheap ones! Unqualified replacement can damage the fee.
• ⚡ Use the Power Saving Mode: Settings → Battery → Power saving mode. This will limit background activity and reduce the load on the processor.
• 🔌 Do not discharge the phone to 0%: the optimal charge range is 20-30%.

Make sure the problem is with the battery:

✅ The phone brakes only when the charge is low (below 30%)

✅ B Settings → Battery visible sharp drawdowns of the charge level

✅ The phone is heated even in simple

✅ Battery age: more than 2 years

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7 Application Conflicts: When Software “Blocks” the System

Some applications may conflict with MIUI, causing freezes or cyclical reboots, most often caused by:

• 🛡️ Antiviruses (e.g. Avast or 360 Security) – they block system processes.
• 🎵 Music players with a widget (for example, Poweramp or AIMP) — They can "hang" the interface.
• 📱 Launchers (such as Nova Launcher or Microsoft Launcher) – sometimes conflict with the shell MIUI.
• 🎮 Emulators (e.g., emulators, PPSSPP Dolphin or Dolphin – overloading the processor.

How to find the "culprit":

1. Load your phone in Safe Mode: Press the Power button → Long tap on Turn off → Safe Mode.
2. If there are no brakes in safe mode, the problem is in one of the installed applications.
3. Remove suspicious programs one at a time, checking performance after each deletion.

If the conflict is caused by a system application (such as Mi Video or GetApps), it can be disabled, but not deleted:

1. Open Settings → Applications → Application Management.
2. Select the problem application → Disable.
3. Confirm the action (administrator rights will be required).

8 Hardware problems: when the "iron" is to blame

If all software methods are tried, but Redmi 9 still slows down, the cause may lie in physical malfunctions:

• 💾 Damaged internal memory (for example, after falling or getting moisture).
• 📶 Faulty module Wi-Fi/Bluetooth — It can cause a freeze when connecting to the network.
• 🖥️ CPU chip dump (rarely, but happens when overheating).
• 🔌 Oxidation of battery contacts - leads to unstable power supply of the board.

How to diagnose hardware problems:

• 🔍 Check for physical damage: cracks on the board, bloated capacitors, traces of oxidation.
• 📊 Run the hardware test: enter the code ##6484## (test of hardware components) or ##64663## (memory test).
• 🔧 If the phone brakes after a fall or water hit, self-repair can aggravate the problem.

⚠️ Note: If the Redmi 9 started to brake after changing the screen or battery in an unofficial service, there is a high probability that the masters damaged the plumes or poorly soldered contacts).

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If the phone is only slowing down when you connect to a charger, the problem is probably the power supply or connector. Try a different cable and adapter before you visit the service.

FAQ: Answers to Frequent Questions