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WARNING: SDHC cards can only be used in SDHC-compatible devices! Not compatible
with devices that support only SD cards!
SDHC (SD High Capacity) is the new generation of the SD card format (Version 2.0).
The cards are formatted using the FAT32 file system. This means that they can be developed up to a capacity of 32 GB
, ready to meet the steadily-growing demands of greater performance and higher capacity.
Class 2 = pw-write min. 2 (MB/sec), pm-move min. 1 (MB/sec), pr-read min. 2 (MB/sec), TFW(avg.) max. 100 (ms), TFW (max.) max. 750 (ms), TFR (4KB) max. 4 (ms)
Class 4 = pw-write min. 4 (MB/sec), pm-move min. 2 (MB/sec), pr-read min. 4 (MB/sec), TFW(avg.) max. 100 (ms), TFW (max.) max. 750 (ms), TFR (4KB) max. 4 (ms)
Class 6 = pw-write min. 6 (MB/sec), pm-move min. 3 (MB/sec), pr-read min. 6 (MB/sec), TFW(avg.) max. 100 (ms), TFW (max.) max. 750 (ms), TFR (4KB) max. 4 (ms)
The SD Association defines 3 speed classes in order to help consumers understand
the performance of the various SDHC cards available. It specifies a minimum rate
for the supported write speeds (Class 2: 2 MB/s, Class 4: 4 MB/s, Class 6: 6 MB/s)
This classification aims to make it simpler to compare the huge variety of manufacturer specifications (e.g. UltraII, high
performance, platinum, ultra performance 150x,...).
Now you can simply glance at the logo to find out the speed class of the card or card reader
. However, on the practical side, one must point out that the classification
of the individual speed classes is only a rough estimate, allowing for wide variations
. This means that there can still be a considerable performance difference between two SDHC
cards in the same performance class.
WARNING: SDHC cards can only be used in SDHC-compatible devices!
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