The HP Pavilion x360 has an HDD storage medium which is better than most portable PCs of a similar spec and age to it. Most 2 in 1 laptops that are a comparable age to it have an SSD storage medium. HDD is a traditional storage drive which stores the information on magnetic disks. HDD drives are slower than other forms of storage such as solid state drives (SSD) and flash drives.
An HDD storage medium is actually the worst storage medium amongst all notebook PCs of a similar age and type to the Pavilion x360.
The best storage medium across similar types of laptop is SSD.