Gigabyte AB-350 Gaming 3 is 100% stable up-to 3600Mhz for me on 1gen Ryzen 1700, and I can test and fiddle around 3800Mhz all day long now.
Though I never found something work in the length for that speed(3800) without errors but you can use the computer/game whatever(at your own risk))
The newest Agesa 18.104.22.168 improved stability at above 3600Mhz-->3800 but the previous 22.214.171.124 worked up to 3733Mhz(3800 was unusable but bootable).
Now you can use 3800Mhz but I can never squash these pesky few errors at times with TestMem5. I think it's CPU-IMC side as SoC voltage plays a large role on it.
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)