The storage speed of this PC is HDD, which is typical of many computers of this type and age. A Hard Disk Drive (HDD) is the traditional storage method for computers. A HDD stores the information on magnetic disks. HDD drives are cheap, but they are slower than Flash and SSD bases storage systems.
Other HDD computers currently available which you might want to look at include the ProDesk 490 G2, or the ProDesk 600 both from HP or the Acer Veriton 4630G ($518.99) which is cheaper.
If the storage speed of this personal computer is not fast enough for you then you might also want to consider the HP EliteDesk 800 G1 Mini (SSD) which is also cheaper.