The HP Z640 has an HDD storage medium which is faster than most many processor core PCs that have been available for a similar time to it. Most many processor core PCs that are a comparable age to it have an SSD storage medium. 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.
Alternative HDD computers currently available which you might want to consider include the HP Z640 (£1,793.96) which is cheaper.
Computers with a faster storage speed that might be worth considering include the HP Z440 (£1,940.75) (SSD), or the Lenovo P900 (£2,018.46) (SSD) which is also cheaper.