This happened to me.
I have M5A97 mobo 4170 Cpu Corsair Vengeance 16GB 2x8GB 1866 modules installed 1 per channel.Board takes up to 32gb.
If I set it to 1600Mhz at stock 4.2Ghz its fine.
If I overclock with Asus Auto Tune it gives me 4611Mhz Cpu 1446Mhz Ram best it can get stable.
Their SPD is 1333, but run at 1600 fine.But if I set them to 1866 it crashes with overclock failed.
So I guess to get them to run at 1866 you need to tweak it a lot manually?
But seriously will it make any performance difference?
I notice none between 1333 or 1600 or overclocked at 1446 no difference.
I think it means they run UP TO 1866, not @ 1866, so you have to tweak it up manually so you will only get something like 1847.
Which is a waste of time.