KitGuru takes a look at the Corsair RM850x (2018) PSU
A quote from the article:
The major difference between the older RM850x and its successor is the shorter, by 20mm, depth of the new model. With the new model Corsair claim to offer excellent performance at a competitive price point, and all with no cost cutting. Our analysis will give you the answers you need to know before spending the money yourself.Corsair RM850x (2018) PSU Review