The HP 640 has an HDD storage media which is faster than most similar spec computers that were launched around the same time as it. Most PCs that have been on the market for a comparable time to it have an SSD storage media. 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 think you might also be interested in some of the alternative HDD computers currently available including because of it's better review score, the HP Z420[plb_2498184_price].