sd

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Lexar雷克沙 USB3.1规格的多功能三合一读卡器:

分别支持SD卡,microSD卡(即TF卡), CF(CompactFlash), 雷克沙 读取速度最高可以达到312MB/S的极速读卡器

背面详细说明支持的CF卡规格包括UDMA7,此外SD、SDHC、SDXC、microSD、microSDHC、microSDXC,SD/microSD UHS-I和UHS-II标准均兼容,UHS-I规格的传输速度可达到170MB/s,UHS-II的传输速度最高可达312MB/s,CF卡传输速度最高可达160MB/s

2019年终好物分享—大嘴盘MC660Pro

What is difference between micro SD, and micro SDHC and micro SDXC cards?

SD stands for “Secure Digital” SD is 2 GB and below.

SDHC stands for “Secure Digital High Capacity”, SD - HC is between 4 and 32 GB.

SHXC stands for “Secure Digital eXtended Capacity”. SD - XC is 32 GB to 2 TB

From the names only you can tell he main difference in all three i.e. storage capacity.

名字

There is no difference in the quality or security or speed.

The transfer speed depends on the “CLASS” of the card mentioned on it and not on whether it is a SDHC card or SDXC.

All, SD, SDHC and SDXC are available in various CLASS ranging from 2 to 10.
CLASS 2 represents 2MB/s transfer speed and so on.

CARDS - WHAT IS UHS-1 ?

“UHS-1” or more accurately “UHS-I” stands for “Ultra High Speed” - 1 and is a speed class for SDHC and SXDC memory cards.

UHS-I has a bus interface speed of up to 104 MB/s.

An SDHC UHS-I card will work in any SDHC compatible device at lower speeds, but to take advantage of the UHS-I speed, a UHS-I compatible device is essential.

An SDXC UHS-I card will work in any SDXC compatible device at lower speeds, but to take advantage of the UHS-I speed, a UHS-I compatible device is essential.

UHS-I compatible cards and devices are normally marked with the symbol below ,”UHS-I” or “I”

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入门款,双槽单读 Kawau 川宇 C396 USB3.0 读卡器
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image-20191213135455691 插上SD卡。
此时读卡器是正面向上的。
image-20191213135523800 插TF卡的时候,是背面向上的。
TF卡和SD卡由于协议和触点都兼容,出于成本考虑,这种只能同时读一张卡的产品,应该就是把两边的触点给连起来,实际只有一套芯片
看来读卡器的性能严重影响到了对于高速存储卡的读取写入速度
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Kawau 川宇 C396 USB3.0 读卡器
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kingston 128G image-20191217104458447
sandisk 128G image-20191217105438885