Xiaomi Redmi 9 slows down: a complete guide to eliminating lags

The situation when the once-quick Xiaomi Redmi 9 begins to react slowly to commands is familiar to many users. A smartphone that was originally positioned as a reliable budgetary device can suffer from a lack of RAM or crowded storage over time. Owners often notice that applications open with a delay, and interface animations become torn. This does not always mean hardware failure, most often the problem lies in software accumulation.

The MediaTek Helio G80 processor in this model is still capable of providing a comfortable work in everyday tasks, if it does not interfere with unnecessary processes. However, the MIUI shell tends to overgrow background services and cache, which over time only increases. If your Redmi 9 started to slow down, you should not immediately carry it to the service or think about buying a new device.

In this guide, we will look at all the possible causes of slowdown and offer step-by-step solutions: you will learn how to properly clean memory, manage autoboot and use hidden functions for developers. The critical factor is often filling the system partition by more than 90%, which causes strong interface friezes. Let's figure out how to fix the situation and prolong the life of your gadget.

Diagnostics of causes of slowdown

Before we start taking drastic measures, we need to understand the source of the problem. Most often, Redmi 9 is slowed down by a banal lack of free RAM. When too many heavy applications are running, the system starts to actively use the paging file, which significantly reduces the response rate. Check the task manager to see which programs consume the most resources right now.

The second common cause is crowded internal storage, where when the space runs out, the Android operating system can't efficiently record temporary files and cache, which causes even simple actions like typing or scrolling through tape to be delayed.

Also worth considering is the impact of updates. Sometimes the new version of MIUI can be too heavy for the previous generation of hardware. If problems started immediately after the software update, you might want to consider rolling back or waiting for an optimization patch. In rare cases, the culprit is overheating of the processor, which artificially lowers the frequencies to protect against damage.

⚠️ Warning: If the phone is warming up even in standby mode and it is straying heavily, it may be a faulty battery or power controller, not the software.

Cleaning the system and memory management

The very first step to take if the Xiaomi Redmi 9 is slowing down is to thoroughly clean the system. Xiaomi's standard "Security" app does a good job of surface cleaning, but the real result requires manual control. Remove unused apps, especially those you downloaded a year ago and never opened.

Pay special attention to messenger folders. Telegram and WhatsApp tend to accumulate gigabytes of cache from photos and videos that you haven't even viewed. Clearing the cache of these applications through settings can free up from 2 to 10 GB of space, which will significantly affect the speed of work. Don't be afraid to delete the cache - your correspondence and contacts will not be affected.

You can use built-in optimization tools to automate the process. Go to the storage settings and use the deep cleaning function. The system will suggest removing duplicate photos, large files and APK installation packages left over from software updates.

Once the space is free, it is recommended to restart the device, which will allow the system to redistribute resources and start the background processes again, but with the space available. If after that Redmi 9 is still running slowly, move to more subtle settings.

Optimization of the interface and animations

The visual part of the MIUI shell often causes perceived lag, which is apparent lag. Transition animations, window openings, and menus require graphics accelerator resources. If you want maximum responsiveness, these effects can be accelerated or completely disabled, and this is especially true for budget devices like the Redmi 9.

To access hidden settings, activate the developer menu. Go to Settings → About Phone and quickly click 7 times on MIUI Version. After you have become a developer, go back to the main settings menu, select “Additional” and find “Developers”.

Inside this menu, scroll down to the Drawing section. Find three options: "Window animation scale," "Scale of transition animation," and "Scale of transition duration of animator." They're 1x by default. Change them to 0.5x or completely disable (0x). Visually, the interface will become "dry," but the response to touch will be much faster.

Also on the developer menu, you can find the item "Background limit of processes": set the limit "No more than 2 processes" or "No more than 3 processes" This will prevent the system from holding in memory many heavy applications that you are not using at the moment, which will free up RAM for the active task.

Managing Autoboot and Background Processes

One of the main reasons why Xiaomi Redmi 9 starts to slow down over time is the uncontrolled autoload of applications, many of which are pre-written and continue to run in the background, consuming traffic, battery power and CPU time, and you can control this process through a special menu.

Go to the Security app (green lightning icon), select Permissions, and find AutoStart. Here you will see a list of all the programs that start with your phone. Leave only messengers (for notifications to come) and system services on. Social media, games and stores are better off - they will start themselves when you open them.

Also, check the battery settings for each application. Go to Settings → Apps → All apps, select an unnecessary program, click on “Power Saving” and select “No Limits” only for the important ones, and for the rest, set “Limitation” to prevent their background activity.

• 🚀 Turn off auto-start for all games and heavy apps.
• 🔋 Set the Battery energy saving mode in the notification curtain to limit background activity.
• 📉 Remove widgets from the desktop that are updated in real time (weather, news).
• 📵 Turn off cloud services sync for applications you rarely use.

After this manipulation, the number of processes in the background will decrease, and RAM will be occupied only by the really necessary tasks, which is especially important for a model with 3 or 4 GB of RAM, where every megabyte counts.

Special MIUI functions for acceleration

There is a hidden feature in the MIUI shell that can dramatically change the behavior of the system, MIUI Optimization, which in some versions of the firmware allows the system to work in a cleaner Android mode, removing unnecessary visual bells and whistles of Xiaomi.

To find this option, go back to the Developer Menu. Scroll down to the bottom. If you see "Enable MIUI Optimization," try turning it off. The phone will alert you to reboot and change icons. Once turned on, the system may run faster, but some MIUI features, such as themes or additional gestures, may stop working correctly.

Another useful tip is to use Second Space mode or guest mode only when necessary. Having multiple active user profiles divides the CPU resources. If you only use one profile, make sure that guest accounts are deleted.

⚠️ Attention: Disabling optimization MIUI This can cause the interface to be displayed incorrectly in some applications, only if other methods have failed and you are prepared for possible visual bugs.

Also worth noting is the memory extension feature. In Redmi 9, it may not be available in stock firmware, but in global versions of MIUI 12.5 and higher, sometimes you can have some internal RAM. If you have this option in Settings → Advanced Settings → Expand memory, activate it. This will add virtual 2 GB to your RAM, which will help in multitasking.

Radical measures: Resetting and reflashing

If neither cleaning nor tweaking helped and Redmi 9 continues to slow down, the final software method is a complete factory reset, which will delete all your data, apps and accounts, bringing your phone back out of the box. Often the only way to get rid of deep system bugs and file conflicts.

Before starting the procedure, make sure to back up important data. Photos, contacts and documents are best saved to your computer or to the cloud. Go to Settings → About Phone → Reset → Erase all data. The process will take about 10-15 minutes.

After reset, take your time to install all the apps at once. Turn on your phone, set up the basic functions, and watch it run clean. If the lags are gone, it means the problem was the software junk. Start installing apps one by one, keeping track of whether braking happens again.

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Once you reset, don't install all the apps from the backup, install only the essentials and use your phone for a couple of days, which will help you identify which app is causing conflicts.

In extreme cases, even if the reset does not work, it may be necessary to flash the device through the computer using the Mi Flash utility. This is a more complex process that requires unlocking the bootloader, and it is recommended only for advanced users. Often it helps to switch from global firmware to Chinese (with the subsequent installation of Google services), or vice versa, since different versions are optimized in different ways.

Hardware limitations and wear

Remember that Xiaomi Redmi 9 was released in 2020, and for today's standards, its specs may be limited.The type of memory eMMC 5.1 used in the device degrades over time.Write and read speeds drop after thousands of rewrit cycles, which physically prevents the phone from running as fast as it did on the day of purchase.

If the phone is constantly warming, it also leads to trottling, which is a decrease in the frequency of the processor for cooling. Check if the speaker or the back cover is glued with a thick cover that interferes with heat removal. In hot weather, the performance of any smartphone drops, and this is normal electronic behavior.

It's also worth checking the battery status. An old battery may not be delivering the required current under load, causing sudden shutdowns or severe performance drawdowns. If the phone is several years old, replacing the battery at the service center can work wonders.

Understanding the hardware limits will help you assess the situation adequately.Redmi 9 is a great budget, but it's not designed for heavy gaming at ultra-sets in 2026-2026.Reducing graphical settings in games to a minimum will greatly improve FPS and stability.

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Integrated approach: The combination of memory cleaning, disabling animations and autoboot control returns 90% of the Redmi 9’s previous performance.

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