Why Xiaomi Redmi 9 is slowing down: a full analysis of the causes and solutions

Xiaomi Redmi 9

In this article, we’ll look at all the possible reasons why the Redmi 9 is slow, from a simple memory shortage to hardware malfunctions. You’ll learn how to diagnose a problem, what settings to optimize, and when to actually go to the service. And we’ll also compare the Redmi 9 to other Xiaomi models for stability — maybe your case is not unique, and the solution has already been found by other users.

⚠️ Important: if the phone started to brake after a fall, moisture or severe overheating, immediately go to the section "Hardware malfunctions" - software methods will not help here.

1. Overloading of RAM (RAM)

Redmi 9

3-4 GB of RAM

How to check the RAM load:

1. Open Settings → About the phone → Memory status.
2. Look at the RAM usage chart. If it's less than 500 MB free, that's critical.
3. Click on “Clean” (but it’s a temporary fix!).

🔹 Why is this happening?

• 📱 Background processes: messaging apps (WhatsApp, Telegram), social media, and games continue to work even after closing.
• 🔄 Autoboot: Many apps run when the phone is turned on and hang in the background.
• 🗑️ Garbage files: Cache and temporary data take place in RAM.

💡

To see which apps consume the most memory, install Developer Options (enables via Settings → About Phone → MIUI version – press 7 times). Then in Settings → Additional → For developers, enable the option “Show Memory Use”.

⚠️ Warning: If the phone still brakes after cleaning RAM after 10-15 minutes, the problem is deeper — perhaps the firmware or hardware is to blame.

2. Completed Storage (ROM)

Redmi 9

32/64/128 GB

10%

📊 How to check:

1. Go to Settings. → Warehouse.
2. If the Available section is less than 3-5 GB (for 32 GB models) or 8-10 GB (for 64/128 GB), it’s time to clean.

🔹 What's taking up space?

💡 Tip: If you install games frequently, use a memory card (up to 512 GB). But remember: not all applications can be migrated to the SD- card - it depends on the developer.

3.Outdated firmware or MIUI failure

Xiaomi

Redmi 9

• 🛠️ Fixes bugs that cause the phone to brake.
• 🔋 Optimizing power consumption (important for battery life).
• 🚀 Performance improvements for older chipsets (Redmi 9 is MediaTek Helio G35/G80).

🔄 How to update firmware:

1. Go to Settings → About the phone → System update.
2. Click on "Check Updates."
3. If a new version is available, download and install (preferably via Wi-Fi).

⚠️ Warning: If the phone gets worse after the upgrade, it may be that the new firmware contains bugs, and then rolling back to the previous version via Fastboot (instructions in the "Reset and Firmware" section) will help.

🔹 Signs of failure MIUI:

• 🐢 Slow animation when opening menus.
• 🔄 Self-involved reboots.
• 📱 Freezes when the screen is unlocked.

4. Viruses and malware

Redmi 9

APK

• 🕵️‍♂️ Steal data in the background (loading the processor).
• 📊 Show hidden advertising (consumes RAM).
• 🔋 Discharge the battery and heat the phone.

🛡️ How to check your phone for viruses:

1. Install antivirus (Dr.Web, Kaspersky, Malwarebytes).
2. Run a deep scan.
3. Remove suspicious apps (especially if they ask for weird permissions, such as accessing SMS).

🔹 Signs of infection:

• 📲 Advertising appears even in standard applications (Calls, Messages).
• 💰 Money is debited from the account (SMS to short numbers).
• 📈 Unexplained traffic consumption (check in Settings) → SIM-maps and mobile networks → Traffic).

⚠️ Warning: If the antivirus finds threats in system files (e.g., /system/app), it may mean that the virus has infiltrated the firmware, in which case only a complete reset or firmware will help.

5. Processor overheating

MediaTek Helio G35/G80

Redmi 9

• 🎮 Long-term gaming sessions (PUBG Mobile, Genshin Impact)
• 📹 Video recordings in 1080p.
• ☀️ Use in the sun or in a hot room.

🌡️ How to check the temperature:

• Install the AIDA64 or CPU Monitor app.
• If the temperature of the processor exceeds 60-65 ° C, this is a critical overheating.

🔥 What to do:

• 🛑 Close all apps and let the phone cool down (10-15 minutes).
• 🧊 Remove the cover (it can block the heat sink).
• 🔧 Clean the charger connector from dust (dust insulates heat).
• 🔋 Do not use your phone while charging (this increases the load).

⚠️ Warning: If the phone overheats even in a simple (e.g., while watching YouTube), this could indicate:

• 🔋 Battery malfunction (bloating).
• 🔌 Problems with the power controller.
• 🧹 Clogged radiator (in active cooling models)

Battery wear and tear

The battery in Redmi 9 (5020 mAh) is designed for 300-500 charging cycles, and then the capacity drops, and the phone starts:

• 🔋 Quickly discharge (less than 4-5 hours of operation).
• 🐢 Brake at a charge level below 20% (system limits performance).
• 🔌 Disconnect spontaneously (even at 30-40% charge).

📊 How to check battery wear:

1. Install AccuBattery (shows real capacity).
2. If the battery is under 80% healthy, it’s time to change it.
3. Also check in Settings → Battery → Battery condition (in some firmware).

🔋 What to do:

• 🔄 Calibration: Discharge the phone to 0%, then charge to 100% without interruption (helps with controller failures).
• 🔧 Replacement: The original battery for the Redmi 9 costs ~1500–2000 ₽ (with work). Don't skimp on cheap ones!

⚠️ Warning: If the battery is swollen (seen by a raised screen or body warp), immediately turn off the phone and do not use it until the battery is replaced - this is dangerous!

Hardware malfunctions

If all the software methods didn't work, the problem could be the hardware.Typical Redmi 9 malfunctions:

🔧 How to diagnose:

• 🔍 Check the phone for falls/blows (cracks, dents).
• 💧 Avoid moisture (spots under the screen, corrosion on connectors).
• 🔌 Try another charger (sometimes the brakes are caused by unstable power supply).

💡 Tip: If the phone starts to brake after a repair (e.g., a screen change), it's likely that the wizard has damaged the plume or misassembled the device.

8.Dumping and flashing: extreme measures

If nothing has worked, radical methods remain:

• 🔄 Factory reset: deletes all data, but returns the phone to "clean" state. How to do: Save important data (photos, contacts). Go to Settings → About phone → Settings reset. Select "Erase all data."

Flip-over:

Fastboot

Recovery

1. Download the official firmware from the Xiaomi website (section Redmi 9).
2. Use the Mi Flash Tool (for PC) or TWRP (castom recovery).

⚠️ Warning: Flashing through informal sources (4PDA, custom ROM) may result in:

• 🚫 Loss of warranty.
• 🔐 Lock the bootloader (unless you unlock it in advance).
• 💥 "Overheading" the phone (if the process is interrupted).