The Lenovo Flex 2 has an HDD storage medium which is better than the SSD storage medium found on most portable PCs that are a similar 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 portable PCs of a comparable age and spec to the Flex 2.
An SSD storage medium is the best storage medium across similar types of laptop.