CAS Latency 21 vs 16. Which is better and how does it affect gaming performance?

[yanajerry]

Currently I have 8 gb 2933 MHz RAM with CAS Latency 21 and I want to upgrade it to 16 gb. So I wonder if I should buy just another one with the same specs or buy 2x8 gb 2666 MHz (it seems that my CPU i3-10100 supports 2666 MHz max so I'm not sure if I need RAM with higher speed) with CAS Latency 16. What will be the difference? Will there be any gaming performance improvements if I buy the one with CL16 in comparison to CL21?

[WarnerCK]

If you have mixed numbers, your computer will only work at the speed of the slowest.

The number is the delay in cycles before the RAM can be read from. Dividing that number by the speed will give you that latency in time: a smaller number or a faster speed means a shorter amount of time waiting.

It makes a bit of a difference, but not terribly much, for most workloads.

[_I_]

lower is better

freq / cl

cl is basically how many freq ticks between read/write cycles