The UX305FA has an SSD storage medium which is better than most portable PCs of this age and type. Most medium processor core notebook PCs that have been around for around the same time as it 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 across all medium processor core notebook PCs that have been available for around the same time as the UX305FA.
The worst storage medium amongst similar types of laptop is HDD.
If you would prefer a portable PC with a better storage medium then you might also want to consider the Elitebook 820 G2[pl_2886802_price] (SSD), or the EliteBook 820 G2[pl_2897415_price] (SSD) both from HP.