Ram Usage Rapidly Fluctuating

Ram usage fluctuating a lot which causes lag like being on a server with bad ping.

https://www.youtube.com/watch?v=Vw3Liz_Vdts This video shows the issue ( look in the top right hand corner and look at how the slime falls). Sorry for the scrubs ep in the background.

In 26c and above its just all the time but in 19a you can recreate the issue with alot of fill clock.