Should I choose 32GB of RAM with CL18 latency or 16GB with CL16 latency for gaming?

Go for 32GB. The capacity bump helps more than the latency difference hurts. In gaming, CL16 vs CL18 at the same frequency is usually a 1-2% frame rate difference you won’t feel, but running out of RAM with 16GB causes stuttering and longer load times in modern games. If choosing between a 32GB CL18 kit and a 16GB CL16 kit, the 32GB wins every time.