Neither has a priority, have to combine the 2, a 1866 CL8 set will easily outperform a 2133 CL 11 set......think of the freq and the CL as side by side steps that go up, for high performance, look to
1600/7 - 1866/8 - 2133/9 - 2400/10 - 2666/11
if that doesn' find something you like or fits the budget, drop the CL a step
1600/8 - 1866/9 - etc