The Slot-in PC has an SSD storage media which is faster than the HDD storage media found on most few processor cores computers that were launched more than two years ago. 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 media is actually the best storage speed across all desktop computers of a similar age and type to the Slot-in PC.
Across comparable types of personal computer the worst storage speed is HDD.
It may also be worth considering one of the other SSD PCs currently available including the MSI DC111 which has better reviews.