The Asus E402MA has an SSD storage medium which is better than most many processor core portable PCs that came out around the same time as it. Most many processor core portable PCs that are a comparable age to it have an HDD storage medium. Flash drives store data in semiconductors on a circuit board rather than using magnetic or optical media. Flash have no moving parts which makes them very fast and reliable.
This laptop's storage medium (SSD) is actually the best storage medium amongst all portable PCs that have been around for a comparable time to the E402MA.
An HDD storage medium is the worst storage medium across comparable types of laptop.