some SuperPi 32M test runs with four Crucial 2133C16 OEM modules:
DDR4-2666:
http://abload.de/img/quad_1333c10_154v_32mg8rca.png http://abload.de/img/quad_1333c11_140v_32mgcqg5.png http://abload.de/img/quad_1333c12_132v_32m6ro1o.png http://abload.de/img/quad_1333c13_126v_32mx7qxh.png http://abload.de/img/quad_1333c14_120v_32mwjrx2.png
DDR4-3000:
http://abload.de/img/quad_1500c12_144v_32m43ofn.png http://abload.de/img/quad_1500c13_136v_32m21p00.png http://abload.de/img/quad_1500c14_130v_32mvaofq.png http://abload.de/img/quad_1500c15_126v_32m05pwy.png
DDR4-3333:
http://abload.de/img/single_1666c14_146v_30grr6.png
Getting 1500MHz on 8GB modules is already hard. Only one of four modules I have would even POST at 1666MHz.