I don't know what to do with this. I have MSI B450 A-Pro and latest bios (24/09/2019) - abba. My CPU is working default only with 3600Mhz and with PBO enabled 3775Mhz (+150Mhz). I cleared CMOS many times and nothing helps. In games i have situation that one core have 3400Mhz, other 3600, and other 4300Mhz. Performance is poor.
I had earlier Ryzen 2600X and it would boost to 4050Mhz without PBO and 4175Mhz with PBO or something like this (over 4000Mhz).
At now with PBO + XFR + limits up to 200Mhz my cpu can't reach base clock.
When i use Ryzen Master for stress test my 3600X is achieving 4175-4200Mhz boost on all cores on 1.46V.
I have the same issue. I previously had a 3600 non X in my system and replaced it with an X version. My bios shows 3.8ghz base clock but windows stays at 3.6. I don't have any problems with my boost clock as I can reach 4.4 on 4 cores and 3.75 on 2 cores. The problem is like the original poster's with a cpu that should have a base clock of 3.8 and it's only 3.6. I have submitted a ticket previously and the response was 'it looks like you're boosting fine so just run it and it will be fine." That is really a crappy answer as it didn't answer my base clock question. I tried to reply and make another ticket but they didn't even respond. I guess I wanted to know if I could delete a registry key or something to reset it for windows or if there was another method I could try. The original poster didn't mention if his bios showed 3.8 or 3.6? In my case the bios showed correct and it's just windows.
I sold this 3600X because even PBO don't work on it (4400Mhz were max). I have Ryzen 3600 now nonX and with PBO max it can boost to 4400Mhz like X version and has same boost base clock.
Don't know why even bothering buying 3600X.