The Flex 15D has a better storage medium than most laptops of this type and age. This laptop has an HDD storage medium, whereas most portable PCs that were launched 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.
This laptop's storage medium (HDD) is actually the worst storage medium across all 2 in 1 laptops that have been around for around the same time as the Flex 15D.
Across similar types of laptop the best storage medium is SSD.