Chunks not loading

[Kutip]

So i am running server for me an my friend on my PC. Everything worked fine, but a few Days ago chunks didn't load for him correctly.

Sometimes it went slow as hell, sometimes they didn't load at all.

We don't have that many machines, so i doubt thay cause it... A quarry, automated melon- and cobblestone-farm. And recently we build an oil pump plus refinery for some fuel.

Do i have to relcate more RAM to the Server, if so: how? Or might there be some other reason?

If there are any threads with a similar problem, i didn't find them and would be pleased if somebody could link me to it.