Question 70% ram usage

[Zaraki Zenken Besin]

I was playing a game and i notice the audio is stuttering and and a few minutes it auto close.
I tried opening task manager and notice ram usage is 70=80%

I have 32gb of ram, how do i know the cause of this sudden high usage of ram?

 

[Lafong]

How do you know it was sudden?

What do you see on the details tab of Task Manager in the working set (memory) column when sorted max at the top?