Here I have another article about high wear resistance stainless steels, leading up to an eventual article on my testing of M398 (read my early analysis here). Where to set the cutoff between “high” wear resistance stainless steels and “medium” I’m not sure, but I also have articles about ZDP-189, S60V, M390, and S30V. To come will be S110V and of course M398.
CPM-S90V was originally named CPM-420V released around 1996 . The patent for the steel  lists a lot of studied compositions and I will not be looking at all of them so I recommend reading the patent if you want to look at all of the tests that were performed.
At that time there were several powder metallurgy stainless steels available, both from Crucible and competitors. Crucible’s first PM stainless was S60V (originally 440V) which I wrote about in this article. Crucible then patented a steel with very high wear resistance called MPL-1, the patent for which was submitted in 1986 . Bohler patented M390 steel in 1988. And Uddeholm released Elmax sometime around 1990 .
By sheer coincidence, the new 940 Benchmade from the previous post has S90V steel. I haven’t ever seen S125V.View Linked Article