The HP Z440 has an SSD storage medium which is faster than the HDD storage medium found on most desktop computers of a similar age and spec to it. 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 PC's storage speed (SSD) is actually the best storage speed amongst all personal computers that are a comparable age to the Z440.
The worst storage speed amongst comparable types of PC is HDD.
If the storage speed of this PC is not fast enough for you then you might want to consider the Zotac ZBOX PI320 ($189.26) (Flash), or the Asus CHROMEBIT (Flash) which also has a higher rating.