Great, so on the MSI B850 Board, with 6000 MHz RAM on the QVL list, you will likely find the following BIOS settings helpful (at least they are for me, also on an MSI board)
EXPO = enabled
FCLK Frequency = 2000
UCLK DIV1 Mode = UCLK = MEMCLK (this will be 3000)
High Efficiency Mode = Enabled
Memory Timing Preset = (start with “Relax” and test, then increase and test again)
For me, this resulted is much better performance in MSFS
In addition to that, on the AMD CPU, you can apply a slight undervolt (under PBO Advanced > Curve Offset > All Core > Negative 10 or 15 value) which reduces heat and leaves thermal room for the boost clock to do its thing.
There is a thread here where quite a few people compare BIOS optimizations