Chunks stop loading in some areas and game becomes unresponsive after playing awhile.

When I spend too much time in a highly built area of my creative world chunks will stop loading and the game will stop processing what i'm doing except pausing. It is a huge problem for me and it stinks because i have had my world for 4 years now. I would love to record and show what i'm talking about here but unfortunately it would take too much data for this website so i'll screenshot instead