Current running 1866 on a h61 board at 1600mhz, 2133 on an amd 970 board that only supports 1866mhz, & 1866mhz EAM on an old amd 760g board that only really supports 1333 but is running at 1600mhz.
You are right, i meant he can't run it at 1866Mhz, the RAM would still run at 1600Mhz but what's the point of paying extra money when you can't run at it's full speed, better to just buy 1600Mhz RAM.