you cannot compare them that way. the CAS latency or CL is measured in clock cycles and as one has more cycles than the next they cannot be measured as such. the inches of one are different than the inches of the other and so the measurements cannot be compared directly.
as clock speeds rise so MUST the CL. my slow DDR3 @1600 has a CL of 9. the faster RAM MUST have a higher CL as there are more cycles per second.
you can only compare like to like, the RAM at 2666 with the lower CL will be faster than 2666 RAM with a higher CL.
that said 13 is a low CAS for DDR4 2400 which is usually 14-17. high end kits have lower CS and much higher prices.
But I have to add, Ryzen seriously improves it's performance with at least 3000-3200mhz RAM with CL16 or CL14. Because memory latency gets into the 110-120 nanosecond range on 1st Gen Ryzen (2nd Gen is like 70).
But with high speed RAM that latency can go down significantly, like 80-60nanoseconds (80 for 1st gen 60 for 2nd gen). Which is absolutely HUGE for any program you run that is at all memory sensitive.
Not to mention that the infinity fabric speeds up with RAM speed which allows faster core to core communication.