Why is it slower to backup a folder than the whole partition?

[stilobix]

I'm having an issue.

I do not understand why is it slower (about 5 times slower) to backup a specific folder in a partition than the whole partition itself (which is much bigger than the specified folder).

Thanks for your help,

[Acronis Support]

Hello stilobix,

Thank you for choosing Acronis Products!

A partition backup is always faster than a file backup because files are not always stored in the adjacent clusters on the disc surface. This effect is called fragmentation. Therefore it is necessary to spend a lot of time to move the sensing head along the disk surface to read some files.
Also it is necessary to locate every file on the disk surface before you can read it.

When you create a partition backup, the data is read and stored to the backup file sequentially. There is no need to move the sensing head more than between two adjacent tracks. There is no need to detect the file structure.

Thank you.
Daniel Pustovoy