The ProBook 640 G1 has an SSD storage medium which is better than most portable PCs that have been on the market for a comparable time to it. Most medium processor core laptops that were released more than two years ago 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 portable PC's storage medium (SSD) is actually the best storage medium amongst all notebook PCs of this age and type.
Amongst comparable types of portable PC the worst storage medium is HDD.
There are a number of other laptops that have an SSD storage media currently available which you might also want to look at including the DELL Latitude E6430 which is cheaper.
If you would prefer a laptop with a better storage medium then you might also want to consider the Lenovo L440 (SSD), or the HP ProBook 650 G1 (SSD).