The HP Pavilion x360 has an HDD storage medium which is better than most notebook PCs of a similar type and age to it. Most similar spec notebook PCs that have been available for around the same time as 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 in fact the worst storage medium across all portable PCs of this type and age.
The best storage medium amongst similar types of portable PC is SSD.
It may also be worth also looking at one of the other notebook PCs that have an HDD storage media currently available including cheaper portable PCs such as the FLEX 15, the Yoga, or the Flex 10 all from Lenovo.
Notebook PCs with a better storage medium that might be worth considering include the Toshiba Satellite U920t (SSD), or the Fujitsu Stylistic Q702 (SSD) which is also cheaper.