SD card which is speed enough to handle 4K videos :

The SD Association today announced a new high-performance option and symbol specifically designed to support a wide array of 4K2K television and video products. A new Ultra High Speed (UHS) Speed Class 3 (U3) symbol 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.

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. Consumers will benefit from a single card that is capable of meeting all of their video, photo, music, document and data storage needs.


 SD Speed Class standards were created to support video recording. SD memory card manufacturers use different types of flash memory to create an SD memory card, so actual transfer speed can vary. Varying speeds make it difficult to determine which card will provide reliable recording of streaming content because recording video requires a constant minimum write speed to ensure a smooth playback. The SD Association defines Speed Class standards indicated by speed symbols to help consumers decide what card will provide the required performance. There are two kinds of speed indications regarding SD bus generation

• Speed Class symbols:
  
• UHS Speed Class symbol:
  

Speed Class and UHS Speed Class* symbols indicate minimum video recording performance to ensure smooth video playback. This is important for camcorders, video recorders and other devices with video recording capabilities. The Speed Classes defined by the SD Association are Class 2, 4, 6 and 10.
UHS Speed Class is designed for UHS** devices only and designates minimum writing performance to record video on UHS products. The UHS Speed Classes defined by the SD Association are UHS Speed Class 1 (U1) and UHS Speed Class 3 (U3).

 

 You'll have to wait for U3-capable devices and cards to begin shooting, but it shouldn't be long before you can produce footage worthy of your Ultra HD TV.