Breaking or placing blocks cause FPS drop (may be duplicate of another issue)

The title says it all. I can provide every single piece of info you want.

This might be a duplicate. But I couldn't find any solution for this in the ENTIRE internet. So I opened this here.
Btw when you see the attachments you could say thats perfectly normal but when I play for longer than 2-3 hours it starts to get very very laggy. Every break drops fps to 0 for nearly 1 second.
Possible solution: Add java garbage collection clear button.