How to check Xiaomi phone for performance: a complete guide with tests and tips

Buying a Xiaomi smartphone is a crucial decision, especially if it is a used device or model from unofficial sales channels. Even a new phone can have hidden defects that will manifest themselves in a week of use: frozen pixels on the screen, battery discharged per hour or not working NFC. This article will help to avoid disappointments – here is a collection of expert verification methods used by service centers and experienced buyers.

We will analyze not only basic tests (camera, speakers, buttons), but also hidden nuances that are not covered by sellers: how to detect battery replacement, check the originality of components or detect traces of motherboard repair. All instructions are adapted for Redmi models, POCO and flagship series Xiaomi 13/14, But it's also good for devices. 2018–2026 release.

1.External inspection: signs of falls and repairs

Start with visual diagnostics, which will take 5 minutes, but will reveal up to 70% of potential problems. Take your phone in your hands and examine it carefully in bright light (preferably daylight).

• 🔍 Body: microcracks on the aluminum frame (especially at the connector) USB-C) On plastic models (Redmi Note 12), check the integrity of the clips of the back lid mount - if they are broken, the phone was taken apart.
• 📱 Screen: swipe across the glass - tangible "steps" at the edges indicate a replacement display. OLED-Xiaomi 13 Pro: Look for yellow spots (burnt-out subpixels) with black background.
• 🔋 Rear cover: on models with a battery of 5000+ mic (POCO X5 Pro) check for bloating - put the phone down on a flat surface and slightly press the corners. If the lid is "playing", the battery needs to be replaced.

Repair marks are often masked, such as sticking a new film on a screen or painting scratches on a frame. To detect them, illuminate a flashlight at an angle of 45.° — On the flagship models (Xiaomi 14 Ultra), note the symmetry of the chamber module: if it is displaced relative to the body, the phone fell or it was unprofessionally disassembled.

⚠️ Attention: On models with IP53 (Splash protection) check the integrity of the rubber pads under the lid SIM-If they are missing or deformed, the phone loses its water protection, which is critical for the Redmi Note 11 Pro.+ newer.

2.Display check: tests for broken pixels and sensor

The screen is the most expensive component of a smartphone, and its defects are not always noticeable on a cursory examination.

• 🖥️ Broken pixels: Enable full-screen color (black, red, green, blue, white) mode. OLED-screens (Xiaomi) 13T) Look for the dead dots, they don’t glow in any color.
• 🎨 Gradient and illumination: on a gray background (RGB: 128,128,128) check the uniformity of the backlight. Yellow or purple spots are a sign of aging of the matrix.
• ☝️ Multi-touch: Use the Touch Screen Test app (available on Google Play). Draw with 5 fingers at the same time - if lines are interrupted, the sensor requires calibration or replacement.

For in-depth diagnostics of the display:

1. Open the Settings. → Screen. → Additional settings → Color mode.
2. Select Standard (not "saturated"!) and check the naturalness of the color reproduction. AMOLED-screen (POCO F5) with a standard profile, white should be neutral, without blue or yellow tint.
3. Turn on Reading (Gray Scale Mode) – if the screen flashes or artifacts appear, the problem is with the graphics chip.

Turn on black background (look for light pixels)

Check multi-touch with 10 fingers

Evaluate the uniformity of the illumination on a gray background

Scroll the screen up and down (look for sensor tracks)

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On models with 120 Hz (Xiaomi) 12T) additionally test the smoothness of the scroll: in Settings → Turn on the maximum refresh rate and scroll through a long list (such as contacts). If the image "breaks" or horizontal bars appear, the problem is synchronizing the display and processor.

Diagnosis of the battery: how to detect replacement and wear

The battery is the second most vulnerable component after the screen, and even if the phone is new, the battery could have been in storage for years or replaced with a non-original one. Here are 3 ways to test:

• 🔋 Code. USSD: Enter ##4636## → Battery information: Compare Charge level (should match indicator) and Status (should be "Good") on 2023 models+ This code may not work for the year - use an alternative.
• 📊 AccuBattery: After 2-3 charging cycles, it will show real capacity. If it is less than 15% less than the declared capacity, the battery is worn out. For example, for the Redmi Note 12 Pro (5000 mAh), the critical value is 4250 mAh.
• 🔍 Physical examination: gently shake the phone -- if something is hanging inside, it's a bloated battery (POCO M6 Pro) check whether the battery is visually deformed.

⚠️ Note: On models with fast charging 120W+ (Xiaomi 13 Pro) check the originality of the charger. Counterfeit can give the declared power, but overheat the battery - this reduces its life by 2-3 times.

If the seller claims that the battery is new, ask for a document from the Xiaomi service center with the serial number of the battery. QR-code that can be checked through the official Mi Verify app.

Never checked.

Six months

Only when I notice problems

Before buying a used phone-->

4.Camera testing: how to spot software tricks

Xiaomi cameras are known for their "software" photo enhancement, but this only works on serviceable modules.

1. Open the camera and switch to Pro mode (manual settings). HDR, AI and all filters.
2. Take a photo on the main camera in daylight (ISO 100, exposure 1/1000). Enlarge the picture to 100% — If the details are “smeared” or artifacts (green/purple spots) are visible, the matrix is damaged.
3. Test autofocus: hover the camera at a distance of 10 cm and gradually move the phone away. If focusing "jumps" or does not work at close range, the problem is in the laser autofocus module (relevant to the Xiaomi 13 Ultra).

Pay particular attention to:

• 📸 Front camera: take a selfie with flash on and off. On cheap models (Redmi) A2) often save on the IR filter - because of this, photos with artificial light are obtained with a pink tint.
• 🌃 Night mode: take a picture of the dark corner of the room. If you see green noise points or strong compression artifacts, the problem is processing algorithms (relevant to the image). POCO X5 Sony-sensored IMX582).
• 🔍 Macro mode: On models with a dedicated macro module (Xiaomi 12 Lite), check sharpness at a distance of 2-4 cm.

On flagship models (Xiaomi 14) additionally test the video shooting in the 8K: Record a 10-second video and check it on your computer. If the video is "braking" or has artifacts, the problem is overheating the processor (Snapdragon 8 Gen 2) or a codec malfunction.

5. Performance and overheating check

Xiaomi smartphones powered by Snapdragon and MediaTek processors are prone to overheating, especially after falls or unskilled repairs.

• 📊 Benchmarks: run AnTuTu or Geekbench 6. Compare the results with references for your model (e.g., run by Geekbench 6, POCO F5 You have to get 500,000 to 550,000 in AnTuTu, and if you're 20 or so down%+, Possible problems with cooling or trottling.
• 🔥 Overheating test: turn the camera on in mode 4K@60fps You can also play the game (Genshin Impact or Call of Duty Mobile) at the same time. 15 Check the temperature of the body for a minute (use an IR thermometer or application) CPU Monitor. Up to normal 45°C, critical value — 50°C+.
• 🎮 Game mode: On models with Game Turbo (Black Shark 5), check if the processor cores are switched off under load. CPU Throttling Test from Google Play.

Pay special attention to memory and storage:

1. Open the Settings. → The phone. → Memory and check if the amount of RAM matches the declared. Xiaomi often encounters “cheats” with memory: for example, instead of 8 GB, 6 GB can be installed. + 2 GB of virtual memory.
2. Run a storage speed test through AndroBench. UFS 3.1 (Xiaomi 13) read speed should be 1500+ MB/s, records - 800+ MB/s. If the values are lower by 30%, flash memory is worn out.

⚠️ Note: On models with dynamic RAM (Redmi Note 12 Pro)+) Some RAM can be reserved for background tasks. To see the actual volume, type memory info into Engineer Mode (#36446337.

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If the phone is very warm without load, check the heat paste on the processor. On Xiaomi models 2020-2022, it often dries after 1.5-2 years. Replacing the thermopaste in the service center costs 1000-1500 rubles, but reduces the temperature by 10-15°C.

6.Diagnostics of sensors and wireless modules

Faulty sensors or antennas may not appear immediately, but they will cause a lot of inconvenience.

For verification 5G and LTE:

1. Put it in. SIM-support-card 5G (For example, MegaFon or Tele2).
2. Enter the engineering code ##4636## → Network information.
3. Check the network type setting: should be displayed NR5G (If you're in the area, on the Redmi Note. 11T Pro and newer also check support SA/NSA.

On models with IR port (POCO M5) Check it through the Mi Remote app, and if the remote doesn't respond to commands or requires precise guidance, the IR sensor is contaminated or damaged.

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If the phone doesn’t catch the network in areas with good coverage, the problem may be in the antenna plume (relevant to Xiaomi after falls) or locking. IMEI (Checked through *#06#).

7. Verification of originality and history of the device

Xiaomi fakes are less common than Samsung or iPhone, but the risk of buying a "gray" device or phone with a criminal past remains.

• 🔍 IMEI: Type *#06# and compare the number with the sticker under the battery (on removable batteries) or in the tray SIM-If the numbers don't match, the phone is made from different devices.
• 📄 Serial number: check it on the official website mi.com/global/verify. On fake models (Redmi) 9 Frequently faked: the site will make an error.
• 🔋 Firmware: Go to Settings → The phone. → Version. MIUI. If the Global version, but the phone was bought in Russia, it could be a “overstitched” device to circumvent sanctions (relevant for 2022 models).+ year-end).
• 🛠️ Service history: ask the seller for a check from Xiaomi Service (if the phone was repaired). On flagship models (Xiaomi 13 Ultra) check the integrity of the seals on the screws of the case.

For models sold through AliExpress or JD.com, check the customs declaration.If the phone is imported as a "gift" or undervalued, it may have unofficial firmware, leading to update and warranty issues.

8 Final Tests Before Buying

If all previous tests are successful, follow the 3 final tests to avoid unpleasant surprises.

1. Water test: even if the phone has protection IP53, Instead, apply a drop of distilled water to the speaker and after 5 minutes check the sound. If it becomes muffled, the seals are damaged.
2. Check connectors: Connect charging to USB-C And you can swing the cable -- if the phone loses connection, the connector is loose, put the headphones in 3.5 mm (if you have one), and check the sound in both channels. POCO M4 Pro often fails left channel.

Stress test

Camera.

Bluetooth

Wi-Fi

GPS

If you buy a phone with your hands, ask the seller:

• 📱 Provide checks from the service center (if there was a repair).
• 🔄 Make a factory reset with you (so that hidden problems do not appear after purchase).
• 📦 Show original box with serial number (must match the number on the phone).

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If the seller refuses to perform tests or demonstrates only selective functions (for example, does not give a test). NFC or 5G), This is a reason to doubt the fairness of the deal.

FAQ: Frequent questions about Xiaomi vetting