Actually, your ram is running at 1866MHz. You see on the 5th line, that's showing your timings 9-10-9-27 at 934 MHz which is showing half the Double Data Rate speed of the ram (that's how ram is reported so DDR = 2x which comes to 934x2=1868). You should see those same numbers for each slot occupied. You're good at 1866.
It is confusing to a lot of people that ram is reported at it's single data rate value but it is what it is.
Hope it helped to clarify things a little.