I managed to get 3066Mhz with C16 with moderate sub-timings, the board just has signalling issues and can't really get 3200 stable unless you have an amazing IMC and top bin B-die.
The VRM is excellent compared to what the other boards around this price range have, but RAM overclocking on the X370 Prime is just a pain in the ass.
If you manage a 100% stable run, don't be 100% confident that it's stable, there are some weird signalling issues that result in memory settings that are stable to possibly become unstable after a cold boot or restart. I've just incorporated 2 cold boots + several restarts into my testing now to make sure everything is stable. 3066 so far seems to be the highest I can get on my 1700 with a B-die kit.
The VRM is excellent compared to what the other boards around this price range have, but RAM overclocking on the X370 Prime is just a pain in the ass.
If you manage a 100% stable run, don't be 100% confident that it's stable, there are some weird signalling issues that result in memory settings that are stable to possibly become unstable after a cold boot or restart. I've just incorporated 2 cold boots + several restarts into my testing now to make sure everything is stable. 3066 so far seems to be the highest I can get on my 1700 with a B-die kit.