5 MB/s.
How does that write speed make you feel? You just cringed didn’t you?
A painstakingly slow write speed like 5 Megabytes per second is flat out pitiful these days. Throwing a dinosaur of a memory card like this into your camera is enough to make your camera stop all together. Yet, it was just a few years ago that we were using SD cards with write speeds like this. Can you imagine shooting sports, portraits, or video with one of these antiquated cards? What about 4K video?
Yeah, we can’t either. Thankfully, the SD Association has recently come out with a snazzy new write speed—the UHS Speed Class 3 to be exact. The U3 (Speed Class 3) Ultra High Speed cards will indicate products capable of recording 4K2K video and will operate exclusively on SDXC UHS-I and UHS-II memory cards and devices and SDHC UHS-I and UHS-II memory cards and devices. New devices offering the UHS Speed Class 3 will be backwards compatible and will work with existing SD memory cards.
The UHS Speed Class 3 defines a sizzling fast 30 Megabytes per second constant minimum write speed to ensure high-quality video recordings. This means 4K2K video, live broadcasts and content can be recorded on high-performance cameras such as Digital Single Lens Reflex (D-SLR), Digital Single Lens Mirrorless (D-SLM), camcorders and video cameras and then played back smoothly. Therefore, a single card will be all you need to store video, photo, music, document, and data!
In order to help you select the performance features you need in an SD card, the SD Association has put together a little guide highlighting the performance symbols that appear on products. This will help you identify feature functionality.
UHS Bus Symbols - SD Memory Cards
UHS-I and UHS-II symbols indicate bus interface for data transfer. UHS Speed Class symbols, such as U1 and U3, indicate minimum write speeds for real-time video recording.
I.
UHS- I bus speed makes the massive storage found on SDXC and SDHC memory cards manageable and even more portable. This symbol is used on SDXC and SDHC products capable of supporting data transfer speeds between the memory card and the device of up to 104 Megabytes per second. Users should pair their devices with memory cards having the same symbol for optimum performance.
II.
UHS-II bus speed makes the massive storage found on SDXC and SDHC manageable and even more portable. This symbol is found on SDXC and SDHC products capable of supporting data transfer speeds between the memory card and the device of up to 312 Megabytes per second. Users should pair their devices with memory cards having the same symbol for optimum performance.
UHS Speed Class Symbols - SD Memory Cards
UHS Speed Class symbols are found on SDXC and SDHC products with either UHS- I or UHS-II symbols. The U1 denotes a 10 Megabytes per second minimum write speed, and U3 denotes 30 Megabytes per second minimum write speed. Users will achieve optimum video recording performance by pairing their devices with the appropriate SDXC or SDHC memory cards with the same marks.
Legacy Speed Class Symbols - SD Memory Cards
The existing Speed Class symbols for non-UHS SD bus mode (this includes non-UHS bus mode operation of UHS memory cards) are Class 2, Class 4, Class 6 and Class 10. They refer to the minimum write speed performance of the memory card for video recording. The symbols are found on SD, SDHC or SDXC memory cards and devices.
Sold on the U3 SD cards now? Well, we just so happen to carry a few different U3 memory cards for 4K and beyond!
Source: SD Association – "NEW SDXC AND SDHC MEMORY CARDS SUPPORT 4K2K VIDEO"