Xiaomi Redmi Note 7
64 GB of internal memory
Full HD
microSD card
In this article, we will analyze the technical limitations of the Redmi Note 7, compare the speed classes (A1, A2, U1, U3, V30, V90), We'll test the actual performance of popular models and give you a checklist to buy, and we'll also uncover 3 memory card myths that 90% of users believe.
Spoiler: Not all 128GB cards are equally useful, and cheap no-name models can shorten your smartphone's life, but that's it.
Xiaomi Redmi Note 7: What to Know Before Buying
Redmi Note 7 supports microSDXC memory cards (up to 256 GB), but with important nuances:
1. Maximum volume – officially announced 256 GB, but in practice the smartphone works with 512 GB (for example, SanDisk Ultra). 512GB). However, the stability of this configuration is not guaranteed: there may be hangings when writing large files or mounting errors after restarting.
2.The card slot is hybrid (SIM2 + microSD. This means that if you use two SIM-You can't install the card at the same time. You have to choose between two. SIM, or.
Support for speed standards:
- ✅ UHS-I (Up to 104 MB/s – works stably
- ⚠️ UHS-II (up to 312 MB/s) – physically inserted, but the smartphone will not be able to use its potential (speed will drop to UHS-I)
- ❌ UHS-III — inconsistent
4. File system - Redmi Note 7 formats maps into FAT32 (For volumes up to 32 GB or exFAT (from 64 GB). NTFS, The smartphone won't see her.
⚠️ Note: Some users are facing an error "SD-The card is damaged after the update MIUI. It's due to a bug in the firmware, not the card.Solution: format the card on another device in exFAT and paste it back in.
Speed classes: what do they mean? A1, U3, V30 How does this affect the Redmi Note 7?
On the memory cards you will see mysterious symbols like A1, U3 or V30. These are not marketing ploys, but speed standards that directly affect performance, and let's see what they mean and what they are relevant to the Redmi Note 7.
Class 1 – an outdated standard denoted by a number in a circle (e.g, ⒸShows the minimum recording speed:
- Ⓒ2 - 2 MB/s (suitable for music only)
- Ⓒ4 - 4 MB/s (low resolution photo)
- Ⓒ10 - 10 MB/s (Full) HD video, but with slowing down)
For the Redmi Note 7 class Ⓒ10 is the minimum, but it is better to focus on more modern standards.
2. UHS Speed Class (U1, U3) — map-relevant UHS-I and UHS-II. The number indicates the minimum recording speed:
- 📱 U1 — 10 MB/s (analogue) Ⓒ10, but with support UHS)
- 🎮 U3 — 30 MB/s (recommended for 4K-video)
For the Redmi Note 7 optimally U3, As the smartphone shoots video in 4K@30fps, This requires a recording speed not lower than 25 MB/s.
3. Video Speed Class (V6, V10, V30, V60, V90) — The number indicates the minimum speed in MB/s:
- 🎥 V10 — 10 MB/s (Full) HD)
- 🎞️ V30 — 30 MB/s (4K, HDR)
- 📽️ V90 — 90 MB/s (8K, camera-room)
Redmi Note 7 will be enough V30, Since the smartphone does not support the shooting in 8K.
4. Application Performance Class (A1, A2) — Shows how fast the card handles random read/write operations (important for running applications):
- 📱 A1 — 1500/500 IOPS (reading)
- 🚀 A2 — 4000/2000 IOPS
If you plan to transfer applications to the map (via Settings) → Annexes → Move it to SD), take A2. There's enough for media files. A1.
| Standard | Minimum speed | Suitable for | Recommendation for Redmi Note 7 |
|---|---|---|---|
| Ⓒ10 | 10 MB/s | Full HD video, photo | ⚠️ Minimum, but it is better to take higher |
| U3 | 30 MB/s | 4K video, games | ✅ Optimally. |
| V30 | 30 MB/s | 4K HDR, photography | ✅ Suitable for video |
| A2 | 4000/2000 IOPS | Launching applications from a map | ✅ If you are moving games/applications |
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Xiaomi Redmi Note 7 is the best set of standards: UHS-I U3 V30 A2. This ensures stable operation with 4K-video and applications.
TOP-5 Memory cards for Xiaomi Redmi Note 7: price-speed comparison
We tested 15 different brands of memory cards and selected the top 5 in price/quality/compatibility. All cards are validated on the Redmi Note 7 with firmware. MIUI 14 (Android 12).
Selection criteria:
- 📊 Compatible with Redmi Note 7 (no mounting errors)
- ⚡ Real read/write speed (tested in AndroBench)
- 💰 Price for June 2026 (data from Yandex Market, Wildberries, AliExpress)
- 🛡️ Guarantee and reliability of the brand
| Model | Volume. | Class speed | Speed (read/write) | Price (June 2026) | Pluses | Cons |
|---|---|---|---|---|---|---|
| SanDisk Ultra microSDXC | 128GB | UHS-I U1 A1 V10 | 100/60 MB/s | ~1 200 ₽ | ✅ Stable work, low heat | ❌ No support. A2 |
| Samsung EVO Select | 128GB | UHS-I U3 A2 V30 | 105/90 MB/s | ~1 400 ₽ | ✅ Best Apps Choice, 10-Year Guarantee | ❌ Higher than analogues |
| Kingston Canvas Go! Plus | 256GB | UHS-I U3 A2 V30 | 170/90 MB/s | ~2 100 ₽ | ✅ High reading speed, water resistance | ❌ Sometimes forging. |
| Lexar Play microSDXC | 128GB | UHS-I U3 A1 V30 | 150/70 MB/s | ~1 100 ₽ | ✅ Best for video. 4K, low-price | ❌ No support. A2 |
| Silicon Power Superior | 256GB | UHS-I U3 A1 V30 | 95/80 MB/s | ~1 800 ₽ | ✅ 5-year warranty, resistant to temperature changes | ❌ Recording speed is lower than competitors |
Best choice for price/quality ratio: Samsung EVO Select 128GB — Despite the higher price, it is justified by the support of the A2 If you have a limited budget, take Lexar Play. 128GB — It is cheaper, but almost not inferior in speed.
The most important thing is Kingston Canvas Go! Plus. 256GB — Best among terabyte cards for read speed (important for running games).
⚠️ Attention: AliExpress and Ozon often sell fakes under the SanDisk and Samsung brands. Check the seller: official resellers must have at least 95% positive reviews and a sign "Original Product"; counterfeits give low prices (for example, SanDisk). 256GB 800 ₽) and lack of warranty card.
How to check your memory card for authenticity and speed after purchase
Even if you bought a card from a trusted store, you can run into a fake card. Here are 3 ways to check it before using it:
1. Verification of the actual volume
Counterfeit products are often understated (for example, instead of 128 GB, 64 GB) to check:
- 📱 Install the app SD Insight (Android) or H2testw (Windows).
- 🔍 Run a full scan - the program will show the real volume.
- ❌ If the amount is less than the declared, return the card to the seller.
2. Speed test
Use AndroBench (Android) or CrystalDiskMark (Windows):
- 📊 Compare the results with the declared characteristics (see the table above).
- ⚠️ If the recording speed is below 10 MB/s, U3 or 30 MB/s for V30 — faulty-card.
3. Visual examination
The original cards have:
- 🏷️ Holographic sticker with serial number (SanDisk and Samsung).
- 🔍 Clear labeling without typos (e.g., "microSDXC" rather than "microSDXC") SD").
- 📦 Branded packaging with protective elements (Kingston has a red stripe on the blister).
Check the reviews of the seller (rating > 95%)
Compare the price to the average market (too cheap) = fake)
Buy only in official stores (SanDisk Shop, Samsung Store)
Demand a check and a warranty card-->
What do you do if you buy a fake?
1. Contact the seller and request a refund (under the Consumer Protection Act, you can return the goods within 14 days).
2.If the seller refuses - write a complaint to the site (Wildberries, Ozon, AliExpress usually side with the buyer).
3. Save the evidence: screenshots of the tests, map photos and packaging.
How to format a memory card for Xiaomi Redmi Note 7
The new card can be unstable if not formatted correctly. Redmi Note 7 supports two formats:
1. FAT32
- ✅ Suitable for cards up to 32 GB.
- ✅ Compatible with all devices (including old cameras).
- ❌ File size limit: 4GB (video issues) 4K).
2. exFAT
- ✅ Suitable for cards from 64 GB.
- ✅ There is no limit to file size.
- ❌ Some devices (such as old ones) GPS-Navigators do not support exFAT.
Step-by-step instructions for formatting:
- Put the card in your smartphone.
- Go to Settings → Memory → Memory Map.
- Press "Format" → "As an internal drive" (if you want to port applications) or "like a portable drive" (for media files only).
- Confirm the action. It'll take 2-5 minutes.
⚠️ Note: If you format a card as an internal drive, it cannot be retrieved and used on another device without being completely cleaned.
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Before formatting, copy all data from the card to the computer – the process erases all information!
Frequent Memory Card Errors in Redmi Note 7 and How to Fix Them
Even with a good memory card, you can have problems, and here are 5 common mistakes and solutions:
1. "SD-The card is damaged"
Cause: Incorrect extraction, file system failure, or virus.
Decision:
- 📱 Connect the card to your PC and check for viruses (Kaspersky Virus Removal Tool).
- 🔧 Format the map in SD Formatter (select "Overwrite format").
- 🔄 If it doesn’t help, try another card (the slot in your smartphone may have broken).
2.The card is not determined
Reasons:
- 🔌 Bad contact (try to remove and insert the card again).
- 📱 Incompatible format (e.g, NTFS).
- 🛠️ Card slot damaged (repair needed).
3.Slow video recording 4K
Reason: The card does not match the speed class (needed) U3/V30).
Solution: Buy a card with a higher class (see table in section 2).
4.Apps are not portable to the map
Reason: The card is formatted as a "portable drive" or does not support A1/A2.
Solution: Reformat the card as an “internal drive” (see section 4).
5.The map is heating up.
Reason: Cheap cards without thermal protection or intense recording (e.g., video shooting in the video game) 4K).
Decision:
- 🛑 Stop using and let the card cool down.
- 🔥 If the heat is constant, replace the card (risk of data loss!).
What if the smartphone doesn’t see the map even after formatting?
Memory Card Myths: What Not to Believe
There are many myths surrounding memory cards that prevent you from making the right choice.
Myth 1: “The larger the volume, the slower the map”
❌ Reality: Speed depends on class (U3, V30, A2), It's not volume. It's Samsung. EVO Select 256GB faster than SanDisk Ultra 128GB, because it supports A2.
Myth 2: “Maps A2 It is only needed for Android applications"
❌ Reality: A2 It speeds up any small file operation, like loading levels in games or opening a lot of photos in a gallery, even if you don't put apps on the map, A2 increase productivity.
Myth 3: “All cards are the same, you can take the cheapest one.”
❌ Reality: Cheap cards without a brand:
- 🔥 Overheated during long recording.
- 🐢 Slow down after 6-12 months (memory degradation).
- 💥 They can lose data when power is cut off.
Savings of 200-300 ₽ You will be buying a new card in a year.
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Do not chase the maximum volume - it is better to take a card for 128 GB of class U3 A2, 512GB with a class U1. The difference in speed will be noticeable to the naked eye.