Why choosing a memory card for Redmi 7 is not as easy as it seems
Xiaomi Redmi 7, released in 2019, is still a popular budget device due to its balanced performance and the possibility of expanding memory. However, not every microSD is suitable for this model – there are nuances that the manufacturer does not mention. For example, the slot for the memory card in Redmi 7 hybrid (combined with the SIM-The maximum supported volume is officially limited to 256 GB, although in practice, 512 GB cards also work.
Most users make two critical mistakes: buying the cheapest card or overpaying for unnecessary specs. In this article, we’ll look at what’s really important for the Redmi 7 and what’s not to be overlooked. You’ll learn why the UHS-I U3 card is better than the Class 10, even if both promise the same speed, and why some brands (like Silicon Power) may be more stable than the more well-known SanDisk.
Redmi 7’s Technical Limits: What You Need to Know Before Buying
Before you run to the store, check the specifications of your smartphone. Xiaomi Redmi 7 supports memory cards microSDXC format (up to 2 TB theoretically), but in practice only cards up to 512 GB work. Moreover, the slot does not support UHS-II - this means that buying an expensive card marked UHS-II will not give a boost in speed, but only increase the load on the battery.
Another important point: Redmi 7 uses a hybrid slot (2). SIM + microSD or 1 SIM + microSD if you plan to use two SIM-If you're writing a card, you can't expand the memory. HD The card must maintain a minimum write speed of 10 MB/s (class) U1 For Class 10. 4K will be required U3 (30 MB/s).
⚠️ Warning: Some memory cards (especially cheap no-names) can trick the system into showing more volume than it actually is. H2testw (Windows or F3 (Linux/macOS).
- 🔹 Maximum volume: up to 512 GB (officially 256 GB, but tested and large)
- 🔹 Supported formats: microSD, microSDHC, microSDXC
- 🔹 Class of speed: Minimum Class 10 or UHS-I U1, for 4K — U3
- 🔹 File system: FAT32 (up to 32 GB or exFAT (64 GB)
Memory Card Speed Classes: What Numbers and Letters Mean
Marking on memory cards is often misleading. For example, the label Class 10 means a minimum write speed of 10 MB / s, and UHS-I U3 already 30 MB / s. But this does not mean that the U3 card is always faster: the real speed depends on the controller and memory type (MLC vs TLC). For Redmi 7, the best choice is UHS-I U1 or U3, but you should not chase UHS-II, since the phone slot does not support this standard.
Another nuance: some manufacturers specify the maximum read speed (for example, 100 MB / s), but the real speed of writing can be 2-3 times lower. For everyday tasks (photos, music, documents) will suffice and 30-50 MB / s, but if you shoot video in 4K or often move large files, take a card with a write speed of 60 MB / s.
| Class speed | Minimum recording speed | Suitable for | Example of model |
|---|---|---|---|
| Class 10 | 10 MB/s | Photos, music, documents | Kingston Canvas Select Plus |
| UHS-I U1 | 10 MB/s | Full HD video, applications | Samsung EVO Plus |
| UHS-I U3 | 30 MB/s | 4K video, games | SanDisk Ultra A2 |
| V30 | 30 MB/s | Professional photography | Lexar Professional 1066x |
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If you often shoot videos on your smartphone, choose cards labeled A2 (Application Performance Class 2) that are optimized for fast application and multimedia.
TOP-5 memory cards for Xiaomi Redmi 7: tested in practice
We tested over 15 memory cards in Redmi 7 and selected those that show stable performance without brakes and errors: slot compatibility, real speed (not only claimed), long-term reliability and price-performance ratio. Importantly, all the cards below are tested on MIUI 12.5 firmware (Android 9).
The only card that showed recording speeds above 80 MB/s in Redmi 7 is Samsung PRO Endurance, but its high price is justified only for extreme loads (for example, a dash camera).
- 🥇 Samsung EVO Plus (UHS-I U3, A2): Best price/speed balance: Real-world record speed is 60-70MB/s. 4K video.
- 🥈 SanDisk Ultra (UHS-I U1, A1): Reliable and affordable, 40-50MB/s, perfect for apps and photos.
- 🥉 Kingston Canvas Go! Plus (UHS-I U3, A2): A good alternative to Samsung. Record speed is 55-65 MB/s.
- 4️⃣ Silicon Power Superior (UHS-I U3, A1): Budget option with decent speed (45-55 MB/s). Often cheaper SanDisk.
- 5️⃣ Lexar Play (UHS-I U1, A1): Optimized for multimedia, recording speeds are 30-40MB/s, but very stable.
Why not take no-name cards?
How to properly insert and configure a memory card in Redmi 7
Even the most expensive memory card is useless if you install it or configure it wrong. Redmi 7 requires:
- Turn off your smartphone and remove the tray for SIM-paper-card.
- Place the microSD in the slot face up (contacts should be directed to the back of the phone).
- If you use two SIM-You have to choose the cards, or the second. SIM, or a memory card (hybrid slot!).
- Turn on the phone and wait for the card identification (it can take up to 1 minute).
- Go to Settings → Memory → Memory Map and select formatting (exFAT is recommended for cards from 64 GB).
Once formatted, you can transfer data from the internal memory to the map.
- Open Settings → Memory → Data Transfer.
- Select files (photos, videos, music) and click Transfer.
- For applications: in Settings → Applications, select the program and click Change → Memory Map (not all applications support portability!).
☑️ Preparation of the memory card for use
Frequent memory card issues in Redmi 7 and how to fix them
Even with the right map, you can have a failure, and here are the most common problems and solutions.
- 🔄 The card is not defined: Check if it's inserted correctly (contacts should be clean). Try formatting it on a PC in the computer. FAT32 exFAT.
- ⚠️ Card damaged error: Often caused by a sharp extract. Format the card via phone (Settings) → Memory. → Format).
- 🐢 Slow work: Check the card speed class (should be no lower than the speed of the card) U1). If the card is old, it may wear out (especially if it is old). TLC-chip).
- 📱 Applications are not portable to the map: Not all applications support this feature. check in Settings → Annexes → [name] → Memory.
⚠️ Note: If the memory card starts to "sprinkle" errors after updating the firmware, try to roll back the system to the previous version. MIUI (For example, 12.0.3.0) were bugs with microSD.
To diagnose card speed, use the AndroBench app (free on Google Play). If the write speed is below 10MB/s (for Class 10), it's time to change the card. Also pay attention to the temperature: if the card warms up while recording, it's a sign of wear and tear or poor quality.
FAQ: Answers to popular memory card questions for Redmi 7
Can I use a 1TB card in Redmi 7?
Why does the memory card slow down when recording video in 4K?
Can I install applications on a memory card?
How to verify the authenticity of a memory card?
Should I buy an A2-marked card?
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For most Redmi 7 users, the best choice is the Samsung EVO Plus 128GB U3 A2 card, which provides stable speed, reliability and compatibility with MIUI firmware.