The Mac Mini Late 2014 has an SSD storage medium which is faster than the HDD storage medium found on most computers of this age and type. Solid State Drives (SSD) store information in transistors on a circuit board rather than on optical or magnetic media. This has the advantage of being much faster than a traditional HDD drive.
This computer's storage speed (SSD) is actually the best storage speed amongst all medium processor core personal computers that have been on the market for more than two years.
An HDD storage medium is the worst storage speed across comparable types of computer.