system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If I'm transferring data from one folder to another in the same SSD, how come the data transfer speed is still so much lower than advertised or tested?

As an example, my Adata XPG S8200 Pro can reach read and write speeds of up to 3500/3000 mb/s and even in testing (using CrystalDiskMark) the supposed speeds are around that range. But when I actually transfer files, even within the SSD, the actual speeds is so much slower?
gpt
First of all, are you *moving* the data or *copying* the data?

**Moving** the data on the same drive does not actually *move* the information on the physical drive. The OS merely changes the pointer to that data to make it appear in a different location within your filesystem. 

In other words, the data will still be stored at index XYZ on the drive, but it's folder (the pointer) is now "D:/Folder 2" instead of "D:/Folder 1"

**Copying** data is a much more intensive process. When you do this between 2 different drives, each drive only needs to perform a single operation (i.e. a read operation on the origin drive, and a write operation on the destination drive.) This means that each drive can devote all its available resources to that single operation.

However, when you copy data on *the same drive*, that drive now needs to perform *two* operations - reading *and* writing. On a single SSD, the data must be read, written to a buffer, erased and rewritten in steps, all using the same controller and resources on that SSD. This can be *much* slower than if copying between two different drives.