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I've ordered micro SD cards multiple times from china, I always check them with H2testw to make sure they are real. However I've noticed something strange about the micro SD XC cards (only beyond 64GB), they have an empty unpartitioned space which is few megabytes, so for example in case of a 256GB micro SD card there are a 32MB empty unpartitioned space and a 235GB partition. If I delete the partition and re-partition the card in Disk Manager this 32MB unpartitioned space disappears and I would assume that the capacity of the new partition would be 32MB larger but no, if I repartition the card, the total size of the card becomes smaller than the original main partition, unfortunately I haven't checked how much, but its capacity will be smaller by a few megabytes or kilobytes, so it's not significant. So my questions are:

Why there is a small empty unpartitioned space on my brand new micro SD card?

Why the capacity of the card shrinks if I repartition the card?

Screenshot

Hatibovics
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1 Answers1

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There are not two partitions. There is 32MB of empty space and a single partition taking up the rest of the space.

Typically space is left unallocated on drives in general cards due to partition alignment and SD cards and SSD in particular to allow the system to align partitions with erase blocks.

In the grand scheme of things having 32MB of unallocated space on a 256GB card is trivial, though Disk Management is showing it in a way that makes it look far more significant than it really is.

In real terms that "big" 32MB area should be a small fraction of a pixel wide compared to the size of the rest of the disk. It is shown large so that you can select and do meaningful things with it if you need to, which you don't really.

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Mokubai
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