The Lenovo Flex 2 15D has an HDD storage medium which is better than most similar spec portable PCs that have been on the market for around the same time as it. Most notebook PCs that have been available for a comparable time 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 similar spec laptops that have been on the market for around the same time as the Flex 2 15D.
The best storage medium amongst similar types of portable PC is SSD.
Notebook PCs with a better storage medium that might also be worth looking at include the Lenovo Yoga[plb_2430247_price] (SSD), or the HP Pavilion x360[plb_2404650_price] (SSD).