The HP ZBook 17 has an SSD storage medium which is better than the HDD storage medium found on most laptops of this spec and age. Solid State Drives (SSD) store data in semiconductors on a circuit board rather than using magnetic or optical media. Solid State Drives have no moving parts which makes them very fast and reliable.
This portable PC's storage medium (SSD) is actually the best storage medium amongst all medium processor core notebook PCs that are a comparable age to the ZBook 17.
An HDD storage medium is the worst storage medium amongst comparable types of portable PC.
Portable PCs with a better storage medium that might be worth considering include the T420s[pl_48433_price] (SSD), or the X1 Carbon[pl_2432329_price] (SSD) both from Lenovo.