If you’re in the market for a new SD card for your camera, drone, phone, or other device, you may be overwhelmed by the various types and speed classes available. It’s important to understand that SD card speed class ratings indicate the minimum write speed of the card, which affects how quickly data can be saved to it.
However, deciphering the different speed class ratings can be challenging, especially for those new to using SD cards. In this article, we’ll break down the differences between SD card speed classes and guide you in selecting the right one for your specific needs.
So, without further delay, let’s get started!
SD Card Speed Classes Explained
Speed is an important factor when it comes to SD cards. The speed class rating of an SD card denotes its minimum write speed or the speed at which it can write data to the card. A higher speed class indicates a faster writing capability of the card.
Before proceed, you can check how do SD cards work>>
There are three different speed class ratings that you may come across, namely, Speed Class, UHS Speed Class, and Video Speed Class. Each of these ratings represents the minimum write speed of an SD card and can help you select the right card for your requirements.
Speed Class
The original speed class rating system was introduced in 2005 and is indicated by a number inside a “C” symbol (e.g. C2, C4, C10). This rating denotes the minimum sustained write speed of an SD card, measured in megabytes per second (MB/s). For example, a Class 10 SD card has a minimum sustained write speed of 10 MB/s. The different speed classes offer varying writing speeds, as given below:
- Class 2: This is the slowest SD card speed class with a minimum write speed of 2 MB/s. Class 2 cards are ideal for basic tasks like storing music or photos, but they may struggle with video or high-resolution images.
- Class 4: Class 4 SD cards have a minimum write speed of 4 MB/s. These cards are a step up from Class 2 and can handle basic video recording as well as larger image files.
- Class 6: With a minimum write speed of 6 MB/s, Class 6 SD cards are a good choice for capturing HD video or shooting high-resolution photos.
- Class 10: This is the most common SD card speed class with a minimum write speed of 10 MB/s. Class 10 cards can handle full HD video recording and are suitable for high-speed continuous shooting with DSLR cameras.
It’s essential to consider your requirements when selecting an SD card. If you need to store a few photos or music files, Class 2 or 4 cards may be sufficient. However, if you plan to shoot video or capture high-resolution images, investing in a higher-speed class card such as a Class 10 is worth considering.
How to check what is your SD card speed? You can download one of the 5 free tools: 5 Best Free SD Card Speed Test Tools.
UHS Speed Class
The UHS (Ultra High Speed) Speed Class rating system, which was introduced in 2009, uses a “U” symbol followed by a number (e.g., U1, U3) to denote its different classes. UHS Speed Class ratings indicate both minimum sustained write speed and minimum sequential write speed, measured in megabytes per second. For instance, a U3 SD card has a minimum sustained write speed of 30 MB/s and a minimum sequential write speed of 30 MB/s.
Aside from the UHS Speed Class rating system, there are also different versions of UHS technology that offer higher transfer speeds. These include UHS-I, UHS-II, and UHS-III, and they are denoted by different logos on the SD card.
The following are the features of the different UHS speed classes:
- U1: UHS Speed Class 1 SD cards have a minimum write speed of 10 MB/s, but they can also support faster write speeds up to 104 MB/s. These cards are ideal for capturing high-speed action shots and 4K video.
- U3: UHS Speed Class 3 SD cards have a minimum write speed of 30 MB/s and can support faster write speeds of up to 312 MB/s. These cards are recommended for professional photographers and videographers who need to capture high-quality images and videos at high frame rates.
- UHS-I: UHS-I SD cards are the most common and offer a maximum bus speed of 104 MB/s. They are compatible with most devices that have an SD card slot and support UHS technology.
- UHS-II: UHS-II SD cards are designed for devices that require even higher transfer speeds, such as professional cameras and video recorders. They offer a maximum bus speed of 312 MB/s, but are only compatible with devices that support UHS-II technology and have a UHS-II-compatible card slot.
- UHS-III: UHS-III SD cards are the latest and fastest type of SD card available, offering a maximum bus speed of 624 MB/s. However, they are still relatively new and are only compatible with devices that support UHS-III technology and have a UHS-III-compatible card slot.
It is important to note that while the speed class rating indicates the minimum write speed of an SD card, the actual write speed may be higher than the rating, depending on factors like the device being used and the type of data being written. Moreover, not all devices may support higher speed class ratings, so it is crucial to verify your device’s specifications before purchasing an SD card. If you are a professional photographer or videographer, it is recommended to use a UHS Speed Class 3 (U3) card.
Video Speed Class
The Video Speed Class rating system was established in 2016 and identified by a “V” followed by a number (e.g. V30, V60, V90). Video Speed Class ratings are tailored explicitly for video recording and reflect the minimum sustained write speed of an SD card when recording video at different resolutions and bitrates.
For instance, a V30 SD card has a minimum sustained write speed of 30 MB/s and can record 4K video at up to 60 frames per second.
Different video UHS speed classes have the following capabilities:
- V6: This video speed class requires a minimum sustained write speed of 6 MB/s and can record standard definition (SD) video.
- V10: With a minimum sustained write speed of 10 MB/s, this video speed class can record HD video up to 720p.
- V30: V30 SD cards require a minimum sustained write speed of 30 MB/s, making them suitable for recording HD video up to 1080p and 4K video.
- V60: This video speed class requires a minimum sustained write speed of 60 MB/s and can record 4K video at higher bitrates.
- V90: The highest video speed class, V90 SD cards necessitate a minimum sustained write speed of 90 MB/s and are recommended for recording high-quality 4K and 8K video.
To know more about V90 speed class read: V90 SD Card: Worth it? [Memory Card Review].
It’s essential to note that not all devices may support higher video speed classes, so it’s crucial to review your device’s specifications before buying an SD card. Additionally, using a card with a lower speed class than what is recommended for video recording can cause problems during playback, such as dropped frames or buffering.
If you want to capture high quality videos read the article: SD Card Speed needed for Video Recording.
Refer to the graphic below to gain a better understanding of the various speed classes of SD cards:
Sometimes you may need to clone an SD card for various reasons, such as creating backups, transferring data to a new card, duplicating setups for multiple devices, or sharing content more efficiently.
Learn how to do it by reading the article: [SD Clone Guide] How to Clone Your SD Cards in Seconds.
Best SD Cards With Each Speed Classes Category
When selecting an SD card, it’s important to take into account aspects like its read and write speeds, storage capacity, and compatibility with your device, which will also impact its cost.
Below are some of the recommended SD cards that offer varying speed class combinations:
Best Class 10, UHS-I, U3, V30 Memory Card
SanDisk Extreme PRO
- Save time with card offload speeds of up to 200MB/s powered by SanDisk QuickFlow...
- Pair with the SanDisk Professional PRO-READER SD and microSD to achieve maximum...
- Shot speeds up to 90MB/s (Write speed up to 90MB/s. Based on internal testing;...
The SanDisk Extreme PRO is widely regarded as one of the best SD cards on the market, thanks to its impressive speed and reliability. With UHS-I, U3, and V30 speed classes, the card is capable of handling high-speed continuous shooting, 4K UHD video, and rapid file transfer.
The card offers a minimum write speed of 104 MB/s and a maximum read speed of up to 200 MB/s, making it perfect for professional photographers and videographers who need to capture high-quality images and videos at high frame rates. In addition, the card is available in a range of storage capacities up to 1TB, ensuring that you have plenty of space to store all your important files.
Best Class 10, UHS-II, U3, V90 Memory Card
SanDisk Extreme PRO
- Tap into pro performance designed for professional and advanced photographers and...
- Super-fast write speeds of up to 260MB/s help rapidly clear buffer time to support...
- Sustained V90 video speeds and UHS Speed Class 3 (U3) deliver cinema-quality 8K, 4K...
If you’re looking for a high-speed SD card that can handle the demands of professional-grade photography and videography equipment, the SanDisk Extreme PRO UHS-II is an excellent choice. With a UHS Speed Class 3 (U3) rating, a Video Speed Class 90 (V90) rating, and a Class 10 rating, this card offers both sustained and sequential write speeds of up to 300 MB/s, making it capable of handling high-resolution photos and video at high frame rates.
The UHS-II technology and the card’s 128GB capacity make it a perfect match for high-end DSLRs, mirrorless cameras, and professional video cameras that support UHS-II technology. It also comes with a lifetime warranty and a downloadable Image Rescue software to recover lost or corrupted files. However, it’s worth noting that this card is only compatible with devices that support UHS-II technology and have a UHS-II-compatible card slot.
Best UHS-II, U3, V60, Class 10 SD Card
Sony TOUGH-M series UHS-II
- Waterproof (IPX8)/ Dustproof (ipx6)3
- Up to 277MB/s read speed and 150MB/s write speed
- Toughness design (18x stronger than standard UHS II card)
The Sony TOUGH-M series UHS-II SD card is one of the best options for those in need of a high-speed, high-capacity SD card. With read speeds of up to 277 MB/s it has a minimum sustained write speed of 150 MB/s and is ideal for recording 4K video and high-speed burst photography. The card is also shockproof, waterproof, dustproof, and X-ray proof, making it durable and reliable in even the toughest environments.
The TOUGH-M series also features Sony’s File Rescue software, which can help recover data that has been accidentally deleted or damaged. With storage capacities ranging from 32GB to 256GB, the Sony TOUGH-M series UHS-II SD card is a great choice for professional photographers and videographers who require a high-performance, reliable storage solution.
Which SD Card Speed Class Fits Your Needs?
The performance of your camera, smartphone, or electronic device can be greatly influenced by your choice of SD card speed class. Speed class, UHS speed class, and video speed class all provide varying levels of performance, with higher speed classes generally delivering faster read and write speeds. If you’re seeking an SD card for everyday use, a Class 10 card is an excellent option.
UHS-II cards offer even greater performance for professional photographers and videographers who require faster speeds. However, UHS-III cards are not yet widely available due to limited device compatibility. With the right SD card, you can ensure that your device performs at its best, whether you’re storing files and documents or capturing high-resolution photos or 4K video.
Not only speed matter in SD card, you should also check out its reliability and capacity. There are 3 types of SD cards, 2 of them being the most popular ones: SDHC and SDXC. To learn the differences between them, read the following article>>>
Thank you for reading this guide!
I hope that it was helpful in teaching you everything you need to know about SD card speed classes. 🙂
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Also Read:
- How Many Pictures a 128GB SD Card Can Hold for my GoPro
- How Many Pictures a 256GB SD Card Can Hold for my GoPro
- 32GB Memory Card: How Much Video Can It Hold?
- Top 7 Best Speedy SD Cards for Osmo Action 1 & 2 & 3
- Sony a7III SD Card Speed Recommendation for Your Best Videos
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