The Mac Mini Late 2014 has an SSD storage medium which is faster than most few processor core computers that were released more than two years ago. Most few processor core computers that have been around for around the same time as it have an HDD storage medium. 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.
An SSD storage medium is actually the best storage speed across all desktop computers of this age and type.
An HDD storage medium is the worst storage speed across similar types of computer.