The Lenovo Flex 2 has an HDD storage media which is better than the SSD storage media found on most laptops of a similar spec and age to it. 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 laptop's storage medium (HDD) is in fact the worst storage medium across all 2 in 1 laptops that have been available for around the same time as the Flex 2.
Across comparable types of laptop the best storage medium is SSD.