Do the B350 bios's have ram timings available to be set manually, like my Crosshair 6?
In my example, if I set the ram speed to 3200 ( rated speed of the Flarex kit I have), then reboot, it goes to 3200 @ 16-16-16-39.
I let it go to Windows, then restart again, hit F2 on the way to get the bios up, and manually set the ram timings to the kit's rated 14-14-14-34.
Where it will then stay forever after, assuming i don't reset it or w/e.
I also have access to all the ram sub timings, which I don't mess with.
If at least the main timings are available to you in the bios, and simply setting XMP does not yield the result you want, this may be a route for you. I cannot say this definitively, since I can't see your bios atm....
*Note. You may need a later bios version than the one you currently have, check mobo maker's website.
For the CH6, more settings became available in later bios's than were available at launch or in the first revisions.