Which SD card to choose for the smartphone Xiaomi Redmi 9: a full guide

Xiaomi Redmi 9 remains a popular device due to its excellent price-performance ratio, but its built-in memory is often not enough for modern applications and media. Owners of this model regularly face the need to expand storage to avoid removing important photos or favorite tracks. A competent choice of memory card allows you to turn a budget gadget into a multimedia center without losing performance.

The memory card market is oversupplied, and Class 10, UHS-I, or A2 labeling can be tricky. A faulty card can lead to interface brakes, video recording errors, or complete loss of data. In this article, we will take a detailed look at the specifications of your smartphone and help you choose the best solution.

It's important to understand that read and write speeds directly affect how fast gallery photos open or how fast a game installs. Using a drive that's too slow will negate the benefits of the Helio G80 processor. Let's look at what standards your phone supports.

Technical limitations and format support

Smartphone Xiaomi Redmi 9 is equipped with a hybrid type slot, which means the possibility of installing or second. SIM-Cards up to 512 GB are supported, although many users successfully use 1 TB drives that were not formally announced at the time of the device's release. However, you should not rely on luck, and the choice of volume should be weighted.

The key is the data interface, which supports UHS-I (Ultra High Speed Phase 1) which means that buying more expensive UHS-II cards will not increase speed because the phone controller will not be able to use them physically, and you will simply overpay for the unused functionality.

Also worth considering is the file system. By default, large-volume cards (over 32 GB) are formatted in exFAT, which is the best choice for Android. If you purchase a small-volume card formatted in FAT32, the system may require formatting it, which will result in the deletion of all data.

⚠️ Attention: Slot for SIM/SD The card is located on the bottom end of the case. Remove the tray only with a special paper clip so as not to damage the mechanism. Do not use sharp objects that can get stuck or damage the contacts.

Speed classes and their impact on the smartphone

The main confusion among buyers arises around the marking of speed classes. To work comfortably with the MIUI operating system, it is important to understand the difference between serial and random reading speeds. The regular Class 10 guarantees only a minimum write speed of 10 MB / s, which is suitable for video, but not enough for running applications.

A more important parameter is the Application Performance Class. Labeling A1 or A2 indicates that the card is able to process many small files at once, which is critical for the operation of messengers, social networks and games. Without this parameter, the phone can begin to “think” when saving screenshots or caching pages.

For 4K video recording (although Redmi 9 shoots in Full HD, the speed margin is useful) or high-bitrate Full HD, the V30 label is recommended. This ensures a stable recording of the data stream without jerks and frame skips. If you plan to use the card as the main one for photos and videos, this parameter becomes a priority.

• 🚀 A2 —Highest performance class for running heavy apps and games directly from the map.
• 📹 V30 — optimal for recording high-resolution video and fast serial photography.
• 💾 U1/U3 — basic recording speed standards, where U3 provide 30 MB/s.
• 📉 Class 10 is the minimum standard for smartphones, but can be slow for modern tasks.

Comparison of popular memory card manufacturers

When choosing a brand, market leaders should be preferred, as they use their own memory chips and provide real declared characteristics. Products of little-known Chinese brands often have fake capacity, which is overflowing after the first recording of the first memory. 10-15 GB, which causes file corruption, and reliability is more important than saving money. 100 ruble.

SanDisk has traditionally been considered a benchmark for its Ultra and Extreme lines, which are highly reliable and often come with an app-based authentication adapter preinstalled, but this is the brand that is most often counterfeited, so you only need to buy them from large chain stores.

Samsung’s EVO Plus and Kingston’s Canvas brands have also proven to be resistant to temperature and magnetic fields, and Kingston cards are often a little cheaper with similar specs, making them a great choice for budget smartphones like the Redmi 9.

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Buy memory cards only in official stores or large electronics chains. Marketplaces are at high risk of running into a fake, even if the seller seems reliable.

Instructions for installation and initial setting

The installation process is physically simple, but software integration requires attention. Once you paste the card into the phone that's turned off and turned it on, the system automatically detects a new storage, and a message will appear in the notification curtain about the setting that you can't ignore.

Android will offer two uses: portable storage or internal memory. The first option (Portable Storage) is suitable for photos, videos and music, allowing you to easily transfer the card to other devices. The second option (Internal Storage) encrypts the card and binds it to a specific phone, but allows you to install applications on it.

When you select the "internal memory" option, the system will alert you to a low card speed if it doesn't meet the requirements. This is a normal security response. If you agree, all data on the card will be deleted during the formatting process, so back up important files on your computer in advance.

⚠️ Warning: Formatting the card as internal memory will make it unreadable on other devices without first resetting.Do not force the card out while the phone is running.

Application portability and storage optimization

Once set up, many users want to bring heavy games and social media to the map. In MIUI, this process is not always automated. You need to go to Settings → Apps → All apps, select the desired application and click Memory. If the app developer has allowed the transfer, there will be a “Move” button.

It's worth noting that even when you transfer, some of the data is still in the phone's internal memory, which is an Android system limitation that you can't get around without root rights, so the memory card won't free up the built-in drive completely, but it will significantly offload it.

For multimedia, it is better to immediately set the camera to save photos and videos on the camera. SD-Open the Camera app, click three bars in the corner, select Settings and activate Save on SD-This will prevent the internal memory from being filled up quickly with high-resolution rollers.

Typical problems and methods of their solution

Sometimes users are faced with a situation where the phone stops seeing the card or gives a reading error, often due to oxidation of contacts or a bad press in the slot. Try gently wipe the contacts of the card with a soft eraser and insert it again, making sure that you fix it tightly.

Another common problem is that the file system can become fragmented and the number of rewrites can get closer to the limit, and then formatting the map through a computer using the SD Formatter utility, which restores the correct structure of the file tables, helps.

If the phone is constantly writing, “Error” SD-If you're debugging, it might be a file system conflict or a boot sector damage on the map itself. h2testw, which will show the real volume and presence of broken sectors.

• 🔍 Check the card contacts for contamination or scratches.
• 🔄 Try formatting the card to the exFAT file system on your computer.
• 📱 Make sure the firmware MIUI Updated to the latest version.
• 🛑 Avoid retrieving the card while writing data or running applications.

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Regular backup of data from SD-Cloud or PC cards are the only way to guarantee the safety of information in the event of a sudden failure of the drive.

Questions and Answers (FAQ)