The HP EliteBook 820 G1 has an SSD storage medium which is better than the HDD storage medium found on most laptops 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 across all similar spec laptops that have been on the market for around the same time as the EliteBook 820 G1.
An HDD storage medium is the worst storage medium across comparable types of laptop.
We think you might also be interested in some of the alternative notebook PCs that have an SSD storage media currently available including the DELL XPS 13 which is cheaper.
If you are looking for a notebook PC with a better storage medium then you might also want to look at the T420s (SSD), or the X1 (SSD) both from Lenovo.