How to speed up the Xiaomi Redmi Note 9: from cleaning cache to deep optimization

Why Redmi Note 9 is slowing down and how to fix it

Owners of Xiaomi Redmi Note 9 often face a slowdown after 1-2 years of active use. Even with the MediaTek Helio G85 processor and 4 GB of RAM, the smartphone begins to “hang” when opening applications, slowly switch between tasks or warm up for no apparent reason. The reasons for the brakes lie not only in the “iron”, but also in the features of the MIUI firmware, which over time is clogged with temporary files, background processes and unnecessary services.

In this article, we will discuss 7 working ways to speed up the Redmi Note 9, from basic (cleaning the cache, turning off animations) to advanced (automation optimization, resetting the cache of the dalvik-cache partition). All methods are tested on current versions of MIUI 14/15 and do not require root rights. If your phone runs out in half a day or applications are decorated at launch, here you will find solutions for these problems.

⚠️ Important: Before any manipulation of the system, check the free space in memory (Settings) → Memory. If it's less than 10 percent of the total, make room first (delete the cache, transfer the files to the memory card). Otherwise, optimization may not work.

1. Clearing cache and unnecessary files

The most common reason for brakes is a crowded cache of applications and system processes. In MIUI, the cache accumulates more aggressively than in “pure” Android, due to the background operation of Xiaomi services (for example, miui.analytics or com.xiaomi.midrop). Clearing the cache will not delete your data, but will free up to 1-3 GB of memory.

How to clean the cache correctly:

📱 Cache of individual applications: go to Settings → Annexes → App management, select a program (like Facebook or Instagram) and click Clear Cache. Repeat for all heavy apps.
🧹 System cache: in the same application management menu, tap three dots in the upper right corner → «Clear the cache of all applications. This will delete the temporary files of all programs.
🗑️ Garbage files: use the built-in Cleanup app (Security) → Click on “Deep Clean” and remove unnecessary ones. APK, Log files and remnants of remote programs.

⚠️ Note: Do not cache system applications like com.android.systemui or com.miui.home manually through the ADB — This can cause the interface to crash. MIUI.

Close all apps (swipe up in the recent menu)

Connect your phone to charge (the process can take 5-10 minutes)

Check the space in memory (should be ≥1 GB)

Backup important data (in case of failure)-->

2. Disable animation and visual effects

MIUI is known for its “beauties”: smooth transitions between screens, animation when opening applications, the effects of blurring in the menu, all of which eat up the resources of the processor and RAM, which is especially noticeable on the Redmi Note 9 with its budget hardware.

How to remove animation:

Activate Developer Mode: Go to Settings → About Phone and tap on MIUI Version 7 times. You will receive a notification “You have become a developer”.
Back to Settings → Additionally. → For developers.
Find the animation block and set the values: 🔄 The scale of window animation → Turn off animation (or) ×0.5) 🔄 Scale of transition animation → Turn off animation. 🔄 Duration of animation → Turn off animation.

💡 Useful tip: if after disabling animation interface seems “sharp”, return the scale to the ×0.5 is a trade-off between speed and smoothness, and you can also turn off Hardware acceleration for individual applications in the developer menu if they slow down (e.g. Google Maps).

Yeah, always for speed.

Only if the phone is slowing down.

No, I like smooth transitions.

I tried it, but I brought it back.-->

3. Optimization of autoboot and background processes

One of the key reasons Redmi Note 9 brakes is that apps auto-start when you turn on your phone and work in the background. Many programs (messengers, social networks, games) are added to auto-boot by default and consume RAM even when you are not using them.

How to manage autoload:

🚀 Disabling Autostart: Go to Settings → Annexes → Application management → Autorun. Turn off autoboot for all applications except messengers (WhatsApp, Telegram) and system services.
🔄 Background activity restriction: in the same application management menu, select the program → «Limitations of background activity» → «Limit. This will prevent the app from using the Internet and the processor in the background.
🛡️ Block notifications: Many apps wake up because of push notifications. disable them for unnecessary programs in Settings → Notifications.

⚠️ Note: Do not disable auto-runs for system applications called com.android. or com.miui. – this can disrupt your phone. Also do not limit background activity for Google Play Services (com.google.android.gms), or Google services will stop working (for example, geolocation).

Annex	Can I turn off autostart?	Can you limit background activity?
Facebook, Instagram	✅ Yes.	✅ Yes.
WhatsApp, Telegram	❌ No (needed for notifications)	❌ No.
Google Play Store	✅ Yes.	❌ No (app updates)
System Services (com.miui.*)	❌ No.	❌ No.

4. reset dalvik-cache cache (without root)

If cleaning a regular cache didn't help, the problem could be in the dalvik-cache, a special section that stores optimized versions of applications for quick download, which over time fragments and slows down the system. Unlike a regular cache, it can't be cleared through settings, you'll need to use receptacles.

How to Reset the dalvik-cache:

Turn off the phone.
Press the Power button + Volume up until the Mi logo appears (this will trigger the recavers).
From the Recovery menu, select Wipe & Reset → Wipe Cache (not to be confused with Wipe Data – it’s a factory reset!).
Confirm the action and restart the phone.

🔧 What it does: Once you reset the dalvik-cache, the system reassembles it again, which eliminates fragmentation and speeds up the launch of applications, and it takes 5-10 minutes and doesn't delete your data. MIUI or installing a large number of new applications.

What to do if the Recavator does not open?

If you hold Power + Volume up the phone just turns on, you turn off Fastboot mode. To turn it on: 1. Turn off the phone. 2. Press Volume down + Power until the screen with the rabbit (Fastboot). 3. Connect the phone to the PC and type the command: fastboot oem edl 4. After that, the Recovery will become available.

5. Update MIUI to the latest version

Redmi Note 9 slowdowns are often due to outdated firmware. Xiaomi regularly releases updates that optimize resource consumption, fix memory leaks and close security holes. MIUI 14, for example, added Ultra Battery Saver, which limits background activity and extends the time without recharging.

How to update firmware:

🔄 Through Settings: Go to Settings → The phone. → Update. If you have an update available, download it and install it. Use the stable version (not beta!).
📥 Manually: if OTA-update does not come, download the firmware from the official website MIUI Downloads (select Redmi Note 9 model, codenamed merlin). Transfer the file to your phone and install via Settings → The phone. → Updating the system → Three points. → Select a firmware file.

⚠️ Note: Before updating, check that:

Battery charge ≥50%;
Free space in memory ≥ 3 GB;
You downloaded the firmware for your model (for example, Redmi Note 9 is merlin, and Redmi Note 9 Pro is joyeuse).

Installing firmware from another model will lead to a blink (breakdown) of the phone!

💡

Updating MIUI is the safest way to speed up your phone, but only if you choose a stable version.Beta firmware can contain bugs that, on the contrary, will slow down.

6.Reset to factory settings (last chance)

If none of these methods worked, you have a hard reset, which is to get your phone back out of the box, and it will delete all the data, apps and settings, but it will get back to the original speed. On the Redmi Note 9, it takes 10 to 15 minutes to reset, and it solves 90 percent of the brake problems caused by software failures.

How to do the reset correctly:

After the reboot, set your phone up as new (don’t restore backup via Mi Cloud – this could bring back old bugs!).

🔄 What to do after a reset:

Install only the necessary applications (avoid junk programs).

💡

If the phone still brakes after reset, check the battery status at Settings → Battery → Battery status. If the capacity has dropped below 80%, the battery may be causing the slowdown (the phone automatically limits performance at low charge).

7. Advanced methods (for experienced users)

If you’re ready to go beyond standard settings, here are some advanced ways to speed up the Redmi Note 9:

🔧 Shutdown MIUI Optimization: in the developer menu (Settings) → Additionally. → For developers, disable the option MIUI Optimization. It removes some of the limitations of the system, but it can disrupt gestures and those.
📉 CPU Limit: If the phone overheats, set a maximum frequency limit CPU through the Performance Control app (requires root). G85 You can reduce the maximum from 2.0 GHz to 1.8 GHz – this will reduce heating without a critical loss of performance.
🗑️ Removal of system applications: by ADB You can uninstall unnecessary Xiaomi services (e.g. com.miui.analytics or com.xiaomi.midrop). --user 0 List of safe packets to remove see forums XDA Developers or 4PDA.

⚠️ Attention: advanced methods require knowledge and can cause the phone to fail. CPU It's going to cause constant reboots, and it's going to cause interface errors when you're not sure, you better consult a specialist.

FAQ: Frequent questions about Redmi Note 9 acceleration

🔋 Why the phone stopped after the update MIUI?

Updates often contain new features that require more resources, and can cause dalvik-cache to become corrupted when upgraded, resulting in slowdowns, solution: reset the cache through the receptacles (see section 4) or reset to factory settings.

🎮 Can I speed up the phone for games (PUBG, Genshin Impact)?

Not only is it hardware important for games, but system settings are also important: Enable performance mode in Settings → Battery → Performance mode. Turn off background processes through Settings → Annexes → Application management → Limit background activity. Use Game Turbo (a built-in Xiaomi app for game optimization). Reduce the graphical settings in the game itself (for example, in the game). PUBG Select “Balanced” Mode instead of Mobile «HDR»).

📱 Should you install custom firmware (for example, LineageOS)?

Custom firmware (like LineageOS or Pixel Experience) can speed up a phone, but have downsides: ✅ Pros: no "junk» MIUI, Best Optimization, Updated Android Updates. ❌ Cons: loss of function (e.g, IR-Blaster or Game Turbo, possible camera or network bugs, installation difficulty. Recommendation: if you are not an experienced user, it is better to stay on the site MIUI And optimize it (see methods above). Castom firmware is suitable for enthusiasts who are ready for experimentation.

🔄 How often should the cache be cleaned?

Clear the cache: 📅 Regular application cache: 1 time every 1-2 weeks (or when there is free memory left) ≤1GB). 🧹 dalvik-cache: 1 time every 3-6 months or after major updates MIUI. 🚨 Signs that it’s time to clean: the phone warms for no reason, applications open for a long time, lags appear when scrolling.

🛠️ Can the phone slow down due to a breakdown?

Yes, hardware malfunctions also cause slowdowns: 🔋 Worn-out battery (capacity) <80%) → The phone limits productivity. 🔥 Processor overheating → due to dust in the case or dried thermal paste. 💾 Damaged memory (for example, after a fall) → Diagnosis: If the phone brakes even after resetting to factory settings, take it to a service center for inspection.