The ThinkPad X1 Carbon has an SSD storage medium which is better than most medium processor core notebook PCs that have been on the market for more than a year. Most notebook PCs of this spec and age 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.
An SSD storage medium is in fact the best storage medium amongst all medium processor core notebook PCs that are a similar age to the ThinkPad X1 Carbon.
Amongst comparable types of notebook PC the worst storage medium is HDD.
If you are looking for a portable PC with a better storage medium then you might want to consider the Elitebook 820 G2 (SSD), or the EliteBook 820 G2 ($729.99) (SSD) both from HP.