The Apple Mac Mini Late 2014 has a faster storage speed than most medium processor core personal computers that have been on the market for a comparable time to it. This Apple personal computer has an SSD storage medium, whereas most medium processor core personal computers that were launched 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 PCs that are a similar age to the Mac Mini Late 2014.
Across comparable types of computer the worst storage speed is HDD.