The HP Stream 11 has a better storage medium than most medium processor core laptops that came out around the same time as it. This notebook PC has an SSD storage medium, whereas most laptops that were released more than two years ago 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 laptop's storage medium (SSD) is in fact the best storage medium amongst all laptops that have been around for around the same time as the Stream 11.
An HDD storage medium is the worst storage medium amongst similar types of laptop.