The Lenovo Flex 2 has an HDD storage medium which is better than most laptops of a similar age and type to it. Most laptops of this type and age 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.
This notebook PC's storage medium (HDD) is in fact the worst storage medium across all similar spec notebook PCs that came out more than a year ago.
Across similar types of notebook PC the best storage medium is SSD.