The DELL Latitude E6540 has an SSD storage medium which is better than most portable PCs of a comparable type and age to it. Most medium processor core laptops that were launched around the same time as it have an HDD storage medium. 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 notebook PC's storage medium (SSD) is in fact the best storage medium across all notebook PCs of this type and age.
The worst storage medium amongst similar types of notebook PC is HDD.
If you want a laptop with a better storage medium then you might want to consider the DELL XPS 13 (£494.59) (SSD).