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Product Details:

Model: Ultra MicroSDHC UHS-I Card Level 10

Usable capacity: 4GB-1TB

Speed class: 10

Overall dimensions: microSDHC （4GB 8GB、16GB、32GB）、microSDXC （64GB、128GB 256GB 512GB 1TB）

Memory card size: 15mm * 11mm * 1.0mm

Adapter size: 24mm * 32mm * 2.1mm

Operating temperature: - 13 F to 185 F (- 25 C to 85 C)

Storage temperature: - 40 F to 185 F (- 40 C to 85 C)

Compatibility: compatible with all host devices that support microSDHC and microSDXC

Package: one memory card (original package)+free sending adapterFor example, a TF card user who has just purchased 4G reported that when connected to the computer, the computer shows that the capacity of this card is only 3.8G. This user was puzzled by this: obviously the memory card is marked with a capacity of 4G, why is it that nearly 200MB of the capacity I paid for back has disappeared? This 200M is enough to hold more than 50 songs, is this a product quality problem or is the manufacturer deliberately missing two pounds? Careful users can find that not only on the memory card will appear in this situation, in fact, in the U disk and even on the mobile hard disk will appear such a situation, a hard disk marked with 250G capacity often on the computer will show only 233G or even less. In fact, this is not the fault of the manufacturer, there are many reasons for this situation, the main reasons are combined:

(1) Errors in the calculation method

Storage device manufacturers use a base of 1000 for 1K when claiming storage capacity, and the operating system uses binary relationships, and the base is 1024 for 1K when the software occupies space after formatting, which makes the storage space when used appear to be less than the actual one. Like what:

Storage vendor standard: 1MB=1,000KB

））1KB＝1，000byte；

Operating system algorithm: 1MB=1,024KB))1KB=1,024byte;

Storage vendor standard: 128MB=128,000KB=128,000,000byte;

Operating system algorithm: 128MB=131,072KB=134,217,728byte;

Regarding the capacity problem, these are normal: 128,000,000÷1024÷1024=122.0703(MB)

For example, the hardware nominal MP3 of 128MB, converted into the recognition capacity of the software is

128MB×1000KB/1024KB=125MB, so there will be a calculation error of 3MB.

The larger the storage product, the greater the algorithm error.

(2) Internal files take up space

After partitioning and formatting, the system will occupy some space on the hard disk for system files to use, like the hard disk, the flash disk also uses the FAT file system, and the FAT file system includes the MBR main boot partition, FAT file allocation table and ROOT directory area, etc., these areas generally occupy hundreds of kb flash memory space, so the total capacity displayed by the operating system and the model capacity of the hard disk There is a difference This is a normal phenomenon.

In addition, due to the problems with the manufacturing of the flash memory chip itself, the flash memory medium is allowed to have BadBlocks, which cannot be used and are not counted as effective capacity.

That is to say, the conversion method of the manufacturer and the computer is different, so that one is that the U disk has a certain system space, resulting in your U disk being smaller than the actual one!

1G=1024MB, think 1000MB, so convert to your 1GB, that is

1000GB/1024*1000=976.5MB There are still some system files, so 970M is normal!

And so on:

2G = about 1.8G

4G = about 3.6G

8G = about 7.4G

16G = about 14.8G