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

Why Xiaomi Redmi Note 9 is slowing down and what to do about it

Xiaomi Redmi Note 9 with a MediaTek Helio G85 processor and 3/4/6 GB of RAM was originally positioned as a budget but productive smartphone. However, over time, even it begins to “hang”: applications open for a long time, animation twitches, and in games there are friezes.

1. Software problems – clogged cache, background MIUI processes, outdated firmware or viruses. 2. Hardware restrictions – wear of flash memory (especially on models with eMMC 5.1), overheating of the processor or a discharged battery. 3. Incorrect settings – on animation, high screen resolution or aggressive battery saving, which stifles performance.

In this article, we will discuss the unique Redmi Note 9 acceleration methods that will not be suitable for other Xiaomi models – for example, optimizing the work with eMMC memory or setting the cores of the Helio G85 through the engineering menu.

1.Cache and garbage cleanup: the first step to speed

MIUI is known for actively cacheing application data to speed up re-launching, but over time, this cache turns into digital junk, taking up up to 5-7 GB of memory. On the Redmi Note 9 with 64/128 GB storage, this is not critical, but on models with 32 GB can lead to lags due to lack of free space.

How to clean the cache correctly:

• 📱 Manual for individual applications: go to Settings → Annexes → App management, select a program (such as Facebook or Instagram) and click “Clear Cache” Warning: Do not clear data (Clear Data) – this will delete logins and settings!
• 🧹 Mass cleaning: Use the built-in Security app (shield icon) → «Cleanup» → «Deep cleaning. MIUI Show how much trash can be removed without harming the system.
• 🗑️ Remove Unnecessary Files: In the same Cleanup section, go to the Big Files tab and delete old videos, APK or error logs (files with.log extension).

Once cleaned, restart the phone is a must, because MIUI reassembles the kernel cache only when rebooted. If the smartphone started to work faster after the reboot, the problem was clogged.

⚠️ Note: Do not use third-party cleaners like Clean Master or CCleaner, which often delete important system files. MIUI, And that's what's causing sensors or cameras to malfunction!

2. MIUI optimization: disabling unnecessary functions

MIUI is not just an Android shell, it's an entire ecosystem with a bunch of background processes, many of which can be turned off without losing functionality.

• 🔄 Interface animation: go to Settings → About the phone, tap 7 times on the "Version" MIUI», To activate Developer Mode. Then go back to Settings. → Additionally. → For developers and install:
• 📊 Auto Sync: Turn off automatic sync for unnecessary accounts (Google, Mi Account) in Settings → Accounts and syncs. This will reduce background activity.
• 🔔 Notification from MIUI: Go to Settings. → Notifications and status bar → Manage notifications and disable unnecessary alerts from system applications like Mi Video, Mi Music or GetApps.

Another hidden productivity eater is geolocation services, and even if you don't use maps, many applications (including system ones) are constantly asking for location, to fix this:

1. Go to Settings → Privacy → Permits → Location.
2. Disable access to geodata for all applications except maps and navigators.
3. In the same menu, select Location Method and turn off the Wi-Fi Scanner and Bluetooth Scanner – they constantly scan the networks even when they are off.

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If after disabling the geolocation, the weather widgets stopped working, add the Mi Weather application to the exceptions in the Auto Start section (Settings → Battery → Auto Start).

3. Set up auto-start and background activity

MIUI aggressively restricts the background activity of applications in order to save battery, but sometimes it works against performance. For example, if the messenger (Telegram, WhatsApp) constantly restarts when switching, it means that the system kills its process.

Settings → Battery → Auto-Start

• ⚡ Allow auto-run for critical applications (messengers, banking programs).
• 🔄 Turn off auto-runs for games and rarely used utilities – they will load longer but won’t eat RAM in the background.

For fine tuning of background activity:

1. Go to Settings → Applications → Application Management.
2. Select an app (like YouTube) and tap “Battery.”
3. Set “No Limits” mode for frequently used programs and “Limit Background Activity” mode for others.

⚠️ Warning: Do not turn off auto-start for system processes called com.android. or com.miui. in the Auto-Run menu.This can cause sensor, camera, or mobile network failures.

4.Memory Optimization: How to Make 3GB of RAM Work Like 6GB

The Redmi Note 9 came in versions with 3, 4 and 6 GB of RAM. If you have a 3 GB model, MIUI will actively use virtual memory (swap), which leads to brakes.

• 📉 Limit the number of background processes: C Settings → For developers, set Process Limit to Maximum 2 Processes in the background».
• 🔄 Enable memory compression (zRAM): In the same developer menu, activate the option “Memory compression” and set the size 1.5 GB (for models with 3 GB of RAM) or 2 GB (for) 4/6 This will compress unused data in RAM, making room for active tasks.
• 🚫 Turn off Adaptive Brightness: This service continuously monitors illumination and consumes up to 100 MB of RAM. Switch to manual adjustment in Settings → Display. → Brightness.

For root-right users, there's a more radical method, which is to change the kernel settings for the Helio G85, which allows you to increase the frequency of eMMC memory and reduce read/write delays. But you can do without root, just use the RAM Expander (SWAP) application from Google Play, which creates a paging file on internal memory.

• For 3 GB of RAM: 1–1.5 GB
• For 4 GB of RAM: 1.5–2 GB
• For 6 GB of RAM: 2–2.5 GB

5. Update firmware and reset settings

If your Redmi Note 9 runs on MIUI version older than 12.5, this may be the main cause of the brakes. Older versions of the shell had problems with memory management and background processes.

1. Go to Settings → About the phone → System update.
2. If you can upgrade to MIUI 13/14 (or at least up to the latest version of MIUI 12.5 Enhanced), install it.The new versions are optimized for the Helio G85 and work better with eMMC 5.1 memory.

If the update didn’t help or it didn’t, do a soft reset (without deleting data):

1. Go to Settings → About the phone → Reset settings.
2. Select Reset All Settings (this won’t delete photos or apps, but will return system settings to factory settings).
3. After reset, do not restore settings from the backup – configure phone manually to avoid carrying old errors.

⚠️ Warning: Before resetting, untie your Mi Account in Settings → Accounts. → Mi Account if you plan to sell your phone, otherwise the new owner will not be able to activate the device due to the link to your account!

6. Radical methods: rollback of firmware and custom solutions

If none of the previous methods worked, radical measures remain: They require more time and technical skills, but could bring the Redmi Note 9 back to factory speed.

• 🔙 Reverse to the old version MIUI: Sometimes new updates contain bugs that slow down the device, for example, many users have noted lags after upgrading to the device. MIUI 13.0.4 To roll back:
• 🛠️ Install custom firmware: for example, Pixel Experience or LineageOS. These firmware lacks a "heavy" shell MIUI They're going to work faster, but you're going to need to install them:
• ⚡ Replacement of eMMC with SSD (Only for the experienced: the Redmi Note 9 uses eMMC 5.1 memory, which degrades over time, and can be replaced with a faster memory in service centers. UFS 2.1 (from Redmi Note 10 Pro), but it's expensive and risky.

Before resorting to radical methods, check the status of the battery. A worn-out battery (capacity below 70%) can cause sudden shutdowns and brakes due to voltage drawdowns. You can check the status of the battery through the AccuBattery app or from the engineering menu (#4636## → “Battery Information”).

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Custom firmware gives an increase in productivity by 30-50%, but deprive you of an official warranty and OTA-Use them only if you are ready to solve any problems on your own.

7. Hardware checks: when 'iron' is to blame

If the software methods didn't work, the problem could be the hardware.

• 🔋 Battery: If the phone turns off at 20 to 30 percent charge or discharges quickly, the battery is worn out. MBJ4084 For the Redmi Note 9).
• 🔥 Overheating: Helio G85 It warms at high loads. Install the app. CPU Monitor and check the core temperature if it's over 70.°C in simple, requires replacement of the thermal paste.
• 💾 eMMC memory: over time, memory cells wear out. Check the health of the drive through AIDA64 (If the Reallocated Sector Count is greater than 10, the memory is degraded and it is time to change it.
• 📡 Module Wi-Fi/4G: A weak signal or a constant reconnection to the network can slow down the phone. Check the speed of the Internet using Speedtest and compare it with other devices.

To diagnose hardware, you can use an engineering menu to get in:

1. Open the Phone app and type ##4636##.
2. Go to the "Testing" tab.
3. Run tests on the display, camera, speaker and sensor, and the red color indicates a malfunction.

⚠️ Warning: If the health setting in the Battery Information section shows the value of unknown or dead, immediately disconnect the phone from charging - this is a sign of critical battery wear that may swell!

FAQ: Frequent questions about the Redmi Note 9 acceleration