The Stream 13 has a better storage medium than most laptops of a comparable age and type to it. This laptop has an SSD storage medium, whereas most laptops of this type and age have an HDD storage medium. Solid State Drives (SSD) store data in semiconductors on a circuit board rather than using magnetic or optical media. Solid State Drives have no moving parts which makes them very fast and reliable.
This notebook PC's storage medium (SSD) is actually the best storage medium across all comparable spec notebook PCs that have been on the market for a similar time to the Stream 13.
The worst storage medium amongst comparable types of notebook PC is HDD.