==========
SD cards
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.. contents::
:local:
Standards
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Acronym Capacity FS Spec Compatibility Name
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SD 128MB-2GB FAT16 SD, SDHC, SDXC
SDHC 4-32 GB FAT32 SDA 2.0 SDHC, SDXC High Capacity
SDXC 64GB-2TB exFAT SDA 3.0 SDXC Extended Capacity
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Ultra High Speed, Phase I (UHS-I):
* 50MB/s (UHS-50)
* 104MB/s (UHS-104)
Ultra High Speed Phase II (UHS-II):
* 156MB/s
* 312MB/s
Speed
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SD Speed Class (a number inside "C" symbol) write speed:
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Class Min Speed
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2 2MB/s
4 4MB/s
6 6MB/s
8 8MB/s
10 10MB/s
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UHS Speed Class (a number inside "U" symbol) write speed:
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Class Min Speed
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1 10MB/s
3 30MB/s
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Video Speed Class (a number after "V" symbol) write speed:
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Class Min Speed
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6 6MB/s
10 10MB/s
30 30MB/s
60 60MB/s
90 90MB/s
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.. note:: UHS-I bus interface can only support V6 to V30 speed class memory cards. UHS-II is
required for V60, V90.
Express Speed Class (a number after "E" symbol) write speed:
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Class Min Speed
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150 150MB/s
300 300MB/s
450 450MB/s
600 600MB/s
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Video resolution minimum requirements:
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Video resolution Speed class
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640x480 (SD) C2, C4, U1, V6
1920x1080 (FullHD) C6, U1, V6
4k C10, U1, V10
8k V60
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https://support-in.wd.com/app/answers/detailweb/a_id/36273/~/specifications-and-compatibility-for-sd%2Fsdhc%2Fsdxc-memory-cards
Specifications and Compatibility for SD/SDHC/SDXC Memory Cards.
https://www.kingston.com/en/blog/personal-storage/memory-card-speed-classes
A guide to speed classes for SD and microSD Cards.