The EliteBook 850 G1 has an SSD storage medium which is better than the HDD storage medium found on most notebook PCs of a comparable age and type to it. 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.
An SSD storage medium is actually the best storage medium amongst all medium processor core notebook PCs that have been around for around the same time as the EliteBook 850 G1.
Amongst comparable types of notebook PC the worst storage medium is HDD.
If you would prefer a laptop with a better storage medium then you might also want to look at the T420s (£1,388.87) (SSD), or the S540 (SSD) both from Lenovo.