According to my information, it is the same product, but with a new model and label designation. Unfortunately, I can't tell you whether there are any improvements on the part of the manufacturer that have not been communicated. For the same price, I recommend you go for the latest model (Z instead of X), i.e. WD30PURZ.

Source: https://blog.dvrunlimited.com/archives...

Thank you very much... I have a Synology with 2x hard drives in RAID 1 and need to replace one. Can I now take a Z even though the old one has an x?