The HP EliteBook 755 has an SSD storage media which is better than the HDD storage media found on most portable PCs of a comparable spec and age 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 media is actually the best storage medium amongst all notebook PCs that have been around for a similar time to the EliteBook 755.
The worst storage medium amongst comparable types of notebook PC is HDD.
Other portable PCs that have an SSD storage media currently available which you might want to consider include because of it's better review score, the Precision M6800[pl_2840243_price], or the Precision M6800[pl_2840243_price] both from DELL or the HP Pro[plb_2883384_price].