Should I bet to 1333 oz since 1866?

Question

RAM

Hello dear experts!
Will memory work from 1333 if I put memory from 1866 into 2 slots?

Answer 1

It will, but at a speed of 1333, although you must understand that you are pairing a bike with a racing car, of course, the bunch will go at the speed of a bike.
More worrying is the presence or absence of the letter L (or even U) in the naming of the type of each bar: DDR3 or DDR3L (DDR3U).
PS: The ideal solution is to install strips of the same characteristics, it's also worth looking at the specification of the motherboard, whether it can use the peak speeds of the strips.