host% dmesg | grep AMD
CPU: AMD Ryzen 3 1200 Quad-Core Processor            (3493.84-MHz K8-class CPU)
  Origin="AuthenticAMD"  Id=0x800f11  Family=0x17  Model=0x1  Stepping=1
  AMD Features=0x2e500800<SYSCALL,NX,MMX+,FFXSR,Page1GB,RDTSCP,LM>
  AMD Features2=0x35c233ff<LAHF,CMP,SVM,ExtAPIC,CR8,ABM,SSE4A,MAS,Prefetch,OSVW,SKINIT,WDT,TCE,Topology,PCXC,PNXC,DBE,PL2I,MWAITX>


# no make.conf:
sudo make -j8 buildworld buildkernel  9467.42s user 1442.92s system 389% cpu 46:37.55 total
./xmr-stak-cpu -c .config.txt
Highest:  254.0 H/s

# with CPUTYPE?=native and after rebuilding and installing world and kernel
sudo make -j8 buildworld buildkernel  9563.52s user 1496.12s system 390% cpu 47:11.52 total
sudo make -j8 buildworld buildkernel  9503.42s user 1447.12s system 388% cpu 46:59.96 total
sudo make -j8 buildworld buildkernel  9504.85s user 1449.94s system 389% cpu 46:55.06 total
./xmr-stak-cpu -c .config.txt
Highest:  253.8 H/s