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SD Card TOP > What's SD (Information : About Speed)
There are two types of expressions in speed. One is the maximum transfer speed, and the other is “SD Speed Class”
This means the maximum speed in write or read operations onto SD memory card.
(*The average performance of these operations is lower than the maximum speed and depends on the situation of the inner status of SD memory card.)
(*The average performance of these operations is lower than the maximum speed and depends on the situation of the inner status of SD memory card.)
Speed Class designates minimum writing performance. It was designed for streaming data recording.The "Speed Class", Class2, 4, 6 and 10 for the current Bus I/F and the "UHS Speed Class" Class 1 works under UHS-Ι Bus I/F. (The Speed Class and the UHS Speed Class are not compatible.)
| Marks | Operable under... | Applications | |
| Speed Class |  |
Normal Bus I/F | SD video recording |
  |
HD — Full HD video recording | ||
 |
High Speed Bus I/F | Full HD video recording HD still consecutive shooting |
|
| UHS Speed Class |  |
UHS-Ι Bus I/F | For higher potential of recording real-time broadcasts and capturing large size HD videos |
UHS-Ι is the new standard for higher-speed bus interfaces defined by the SD Association as part of the SD Memory Card Specification Ver. 3.01, which provides up to 104 MB/s performance.
| Bus Mode | Bus Speed | Speed Class |
| UHS-I (Ultra High Speed) | Up to 104 MB/s | UHS Speed Class 1 |
| Conventional (High Speed or Default Speed) |
Up to 25 MB/s | Speed Class 2, 4, 6, 10 (Higher Speed Class covers lower class performance.) |
