I intend to buy an Intel i5 12600k with it?One figure of merit is to divide the speed by the timing.
In your case, they both come to the same value of 200.
What is your cpu?
If it is ryzen, tend to buy faster ram.
If it is intel, ram speed is not so important.
If you will make significant use of the integrated graphics, pick the 3600 speed.I intend to buy an Intel i5 12600k with it?