I belive that 8 threads is the optimal number of threads for the ryzen 6 core because of the l3 cache. , yeah 400 hashes is abit little you should probably get between 470-550h/s
With version 3.8 and large pages enabled on windows i did get 485 hashes
settings were as follow: 3.8ghz overclock cpu , voltages auto , 8 threads
I don't have large pages enabled - will have to reboot to set that - but so far setting "-t 8" has resulted in more CPU usage - close to 80% - and *less* H/s - now averaging about 360!?! I even tried re-enabling the devfee and no difference (except it wasting 40 seconds trying to connect to one of the pools that couldn't be reached - not cool, Claymore).
So I don't know how you are getting >470 H/s out of this miner...
Its probably because you havent enabled large pages, there is a guide somewere how you do it.