The Flex 15D has a better storage medium than most notebook PCs of this age and type. This notebook PC has an HDD storage medium, whereas most laptops of a comparable spec and age 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.
This portable PC's storage medium (HDD) is actually the worst storage medium amongst all 2 in 1 laptops that were launched around the same time as the Flex 15D.
Amongst similar types of portable PC the best storage medium is SSD.
If you want a portable PC with a better storage medium then you might want to consider the Lenovo Yoga (SSD), or the HP Pavilion x360 (£382.66) (SSD).