The HP Z840 has an HDD storage medium which is faster than the Flash storage medium found on most desktop computers of a comparable age and type to it. 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.
We compared all the other HDD desktop computers to this desktop computer and we think cheaper desktop computers such as the Lenovo P900 is also worth considering.
If the storage speed of this many processor core computer is too slow for you then you might also want to consider the Thinkstation P500 (SSD), or the P900 ($3,232.33) (SSD) both from Lenovo or the HP Z640 (SSD).