
What Do SD Card Symbols Really Mean?
Share
What Do SD Card Symbols Really Mean?
If you've ever purchased an SD card, you may have noticed a variety of symbols and numbers printed on the card. While these markings might seem confusing at first, they actually provide crucial information about the card’s speed, capacity, and performance. Understanding these symbols can help you choose the right SD card for your specific needs, whether you're a photographer, videographer, or just someone looking for reliable storage.
1. Storage Capacity (GB or TB)
One of the most obvious symbols on an SD card is its capacity, measured in gigabytes (GB) or terabytes (TB). This indicates how much data the card can store. Common sizes include 32GB, 64GB, 128GB, 256GB, and 1TB. For high-resolution video or professional photography, higher capacities are recommended.
2. Speed Class Rating (C)
The Speed Class rating tells you the minimum write speed of the card, which is crucial for recording video or transferring large files.
- Class 2 (C2) – Minimum 2MB/s
- Class 4 (C4) – Minimum 4MB/s
- Class 6 (C6) – Minimum 6MB/s
- Class 10 (C10) – Minimum 10MB/s (suitable for Full HD video recording)
3. UHS Speed Class (U1 or U3)
UHS (Ultra High Speed) ratings indicate faster performance and are essential for 4K video recording.
- U1 – Minimum 10MB/s
- U3 – Minimum 30MB/s
4. Video Speed Class (V10, V30, V60, V90)
Designed for video applications, this symbol shows the card’s ability to handle high-resolution video.
- V10 – 10MB/s (suitable for Full HD video)
- V30 – 30MB/s (4K video)
- V60, V90 – 60MB/s or 90MB/s (8K video)
5. Application Performance Class (A1, A2)
If you use your SD card in a smartphone or tablet, look for the A1 or A2 rating. These indicate optimized performance for running apps.
- A1 – 1,500 read IOPS and 500 write IOPS
- A2 – 4,000 read IOPS and 2,000 write IOPS
6. Bus Speed (UHS-I, UHS-II, UHS-III)
This symbol indicates the card's maximum transfer speed, with additional markings like I, II, or III referring to the bus interface, where higher numbers signify better performance for high-speed data transfer.
- UHS-I – Up to 104MB/s
- UHS-II – Up to 312MB/s (identifiable by an extra row of pins)
- UHS-III – Up to 624MB/s
7. SDHC vs. SDXC vs. SDUC
- SDHC (Secure Digital High Capacity) – 4GB to 32GB
- SDXC (Secure Digital Extended Capacity) – 64GB to 2TB
- SDUC (Secure Digital Ultra Capacity) – 2TB to 128TB
Final Thoughts
Understanding these symbols can save you time, money, and frustration by ensuring you choose the right SD card for your needs. Whether you're shooting 4K videos, running apps on your smartphone, or simply storing files, knowing what each marking means will help you make an informed purchase.
For high-quality SD cards at competitive prices, check out Top Select’s SD card collection here, where we offer reliable storage solutions for professionals and businesses alike!