Memory bug

I recently built my new computer and Noticed a bug where when i open a world my memory goes up to 88% and gives me a lag spikes then goes to 0% and repeats

What I expected to happen was my minecraft to not have these constant lag spikes when i get 200+ fps

*What actually happened was I get lag spikes every time my memory reaches 88% (takes less than 1 minute) *

I dont have to do anything to make the bug happen it just constantly happens

EXAMPLES
https://gyazo.com/ac1d34e3a80de07f05dc8a2bcc1dd484
^as u can see when my memory reaches 88% it drops my fps to near 0
This happens on all versions of minecraft