The Flex 15D has a better storage medium than most portable PCs of this spec and age. This portable PC has an HDD storage medium, whereas most laptops that have been on the market for a similar 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 across all laptops of a comparable age and type to the Flex 15D.
Across comparable types of laptop the best storage medium is SSD.