Memory cards provide electronic storage space for digital media such as photos and videos. If you own a digital camera, camcorder, drone, or mobile device, chances are you use a memory card. Which memory card you need can best be found in the operating instructions or on the manufacturer's website. However, we have also created the following guide to explain the differences between SD memory cards.
Memory card types
The 3 main types of memory cards are SD Mini, SD Micro, and SD. Each type also has classes that indicate its storage capacity. The most popular classes are SDHC and SDXC.
SD or SDSC (Secure Digital Standard Capacity): maximum storage capacity of 2 GB
SDHC (Secure Digital High Capacity): More than 2 GB to 32 GB storage capacity
SDXC (Secure Digital Extended Capacity): More than 32 GB to 2 TB of storage capacity
An average user can store hundreds or even thousands of photos and video clips on a 32GB or 64GB card. Hardware devices that support newer standards are backward compatible with older standard cards, but newer standard SD cards cannot be used in hardware devices that only support older standards.
Speed of memory cards
Memory card speed is measured as the maximum number of bytes per second that can be transferred between the SD card and the host device (smartphone, digital camera, drone, etc.). This is especially important if the cards are used in camcorders or for video recording, as the speed of the card will limit the video resolution.
Read speed is an indicator of how fast a file can be opened from the memory card. So when you are retrieving a photo from the camera or trying to transfer movie data from your memory card to your phone. Write speed measures the card's ability to store data on the memory card.
The most common way to indicate memory card speed used to be a simple class number, which looks like a number in a circle. Cards can be rated as Class 2 (minimum write speed of 2MB/s), Class 4 (4MB/s), Class 6 (6MB/s), or Class 10 (10MB/s). It is important to know that these are minimum values. So it's entirely possible for a card to be able to reach higher speeds, but these values give an idea of what can at least be expected.
More recently, writing speed has been classified using a UHS speed rating that appears as a 1 or 3 in a “U”. UHS-1 cards achieve a minimum of 10 MB / s, while UHS-3 cards promise 30 MB / s.
Some SDHC and SDXC cards also support Ultra High Speed (UHS) classification, which offers higher data transfer rates. A Roman numeral is often seen on the cards to indicate the speed of the card interface in relation to the Ultra High Speed classification. UHS-I cards reach up to 104MB/s, and UHS-II boosts speeds up to 312MB/s.
Test memory cards
Storage Capacity - It is important to remember that a memory card will never be used to its full storage capacity. The manufacturer has to integrate the file system into the memory card, which takes up a certain amount of storage space. Storage capacity varies from card to card and from manufacturer to manufacturer. For example, a 124GB card should have at least 119GB of storage capacity available.
When testing the speed of a memory card, it is important to use a card reader with a USB 3.0 port and to ensure that the host device (e.g. laptop, smartphone) supports USB 3.0. USB 3.0 enables faster transfer rates between the memory card and the host device (up to 10 times faster in some cases). When using a card reader with a USB 2.0 port or a device that only supports USB 2.0, the speed of the memory card cannot be measured accurately.
The easiest way to test the storage capacity of a memory card (in Windows) is to right-click on the D: drive (or the location where the memory card is located) and select "Properties". On the General tab, you should see the memory card's used and available space. The memory card can be checked for possible system errors on the "Extras" tab.
The second step is to test the memory card speed. To do this, software from a third party must be downloaded. Some of the most common memory card speed testers are ABC, XZY, and FDE. The software provides the reading and writing speed of the card. At ENJOOY, we randomly test our memory cards with ABC software and USB 3.0 card reader to ensure memory card speed and storage quality.