The D 5700BA has an SSD storage medium which is faster than most computers of a comparable age and spec to it. Most few processor core desktop computers that are a comparable age to 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.
This desktop computer's storage speed (SSD) is in fact the best storage speed across all desktop computers of a comparable spec and age to the D 5700BA.
An HDD storage medium is the worst storage speed amongst similar types of desktop computer.
If the storage speed of this PC is not fast enough for you then you might also want to look at the Apple Mac Mini Late 2014 (£657.11) (Flash).