Only gotten 3200Mhz stable... with a memory kit that could do 3733Mhz stable on a gigabyte B350 board.
Basically the board outright refuses to boot/POST too often to manage above 3200Mhz in any meaningful manner. (it just resets)
I could get 3333Mhz to boot on occasion but reboot and you got a reset and have fun trying to get it to boot again. (never had it error free either)
There are way to many limits/gimmicks with regard to memory on this board it's outright painful to try to OC it.
Try too low procODT and the board just fails to POST (though the memory likes the lower procODT better), and try above 1.400V and the board starts to refuse to POST more and more... Basically that's the limit it will do 90% of the time.
That and many missing memory setting features are missing from the BIOS outright like CAD BUS settings. <-- those are critical to a successful high OC to tweak.
Mem voltage is limited to +0.300V so with a 1.200V kit 1.500V is max but as said above anything above 1.400V is a nightmare, it resets 95% of the time.
I think most issues are just bad BIOS implementations/settings.
The board always does a double post/boot, I think some settings are set wrong in there which causes the resets. I would love to be able to stop the double post. Anything unstable and it 90% of the time will reset you settings without allowing you to get to start to see how they fare.
Gigabyte just let you use whatever you wanted how bad it might have been so you could tweak it endlessly. This board just resets anything that is "bad" without letting you try it. Some kind of "safety" feature.
NEW: Biostar x480GT8 ~4.0Ghz CPU, 3200Mhz RAM.... not really better
OLD: Ryzen 7 1700 @ ~4.0Ghz, Gigabyte GA-AB350 Gaming 3, F25 BIOS Agesa 126.96.36.199
4x8Gb Kingston HX434C19FB2K2/16 3466C19 1.2V @ 3733Mhz 16.(17).188.8.131.52.tRFC 568 1T 1.490V (Micron E-die 16nm)
Corsair LPX 2x8Gb 2666C16R @ 3200Mhz 14.(17).184.108.40.206...(260) 1T1.470V (Micron B-die 25nm)