Understanding Memory Card Performance
Key Terms Explained
When choosing a memory card, understanding the various performance ratings and technical terms can be overwhelming. Terms like UHS speed class, video speed class, and bus interface all impact how well a card performs for different tasks, from capturing high-resolution photos to recording 4K video. In this guide, we break down the key specifications and what they mean, helping you select the right SD or microSD card for your needs. Whether you’re a casual user or a professional photographer, knowing these terms ensures you get the best performance and reliability from your storage device.
Video Speed Class: V10 vs V30
The Video Speed Class rating determines how
well a memory card can handle video recording.
- V10: Supports a minimum sustained write
speed of 10MB/s, suitable for Full HD (1080p)
video recording. - V30: Ensures a minimum sustained write
speed of 30MB/s, making it ideal for 4K UHD
video recording and high-bitrate content.
Speed Rating: U1 vs U3
The UHS Speed Class (Ultra High Speed)
rating helps determine a card’s performance
for continuous video recording and burst
photography.
- U1 (UHS Speed Class 1): Guarantees a
minimum write speed of 10MB/s, suitable for
Full HD video. - U3 (UHS Speed Class 3): Requires a minimum
write speed of 30MB/s, ideal for 4K UHD video
and professional applications.
What Does Class 10 Mean?
The Class rating represents a memory card’s
minimum write speed. Class 10 means the card
can sustain a minimum write speed of 10MB/s,
making it suitable for HD video recording and
general storage applications. It is the highest
rating in the standard Speed Class system,
before moving into UHS Speed Class (U1/U3) and
Video Speed Class (V10/V30).
A1 vs A2: App Performance Class
Application Performance Class ratings measure
how well a memory card handles running apps
and processing data.
- A1: Supports random read speeds of 1500
IOPS (input/output operations per second)
and write speeds of 500 IOPS, enabling
smoother app performance on mobile
devices. - A2: Provides faster speeds – 4000 IOPS read
and 2000 IOPS write, making it better for
gaming consoles, high-performance apps,
and multitasking.
Read vs Write Speeds: Why They Matter
- Read Speed: Determines how quickly data can be accessed and transferred from the memory card to a computer or device.
⸰ Example: A 100MB/s read speed allows you to transfer 1GB of data in about 10 seconds. - Write Speed: Determines how fast data is saved onto the card. A higher write speed is essential for continuous burst photography and recording high-resolution video without buffering.
⸰ Example: A 10MB/s write speed takes 100 seconds to save a 1GB file, whereas a 60MB/s write speed would take only 16 seconds.
What Faster Read / Write Speeds Enable
- Smoother 4K UHD and Full HD Video Recording – Prevents dropped frames and lag.
- Faster File Transfers – Move large video files, photos, and documents quickly.
- Better Performance for Drones & Action Cameras – Ensures seamless high-speed recording.
- Enhanced Mobile & Gaming Performance – Faster app launches and reduced loading times.
Whether you need a memory card for everyday use, high-speed performance, or professional-grade storage, Verbatim offers a reliable and high-quality solution for all your digital storage needs.
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