RAM not utilizing 100% in my Windows 10 PC

Hello all,

I am not sure why my Windows not detecting all of RAM capacity. I have now built my (first) PC for about a month and since it’s running I have the same problem, Windows is detecting only 16 out of my 32GB of RAM,

I tried to take out and on again the RAM but I know it’s not the source of the problem Why? Because several software like CPU-Z or GPU-Z detects well 32GB of RAM but CCleaner and Windows only maximum to 16 GB. I’ve also tried to change max memory in misconfigure
but nope, it doesn’t work.

Does anyone have a clue about this?

Thanks!