Why is it after a while I start getting huge lag spikes?

[Projekt]

After I've been playing FTB Infinity for a while (and this happens with all modpacks) I start getting increasingly large lag spikes that forces me to shut down Minecraft and re-open it again.

Once I'm back on, they won't occur for about another hour or two. It's getting really annoying and I'm not understanding as to why this is happening.

I have an i5 Skylake, and 8GB of RAM. 3GB is going into FTB. I really shouldn't be lagging at all.

Anyone have any clue at all as to why this is happening?

 

[Kevin van Rijzewijk]

I got the game issue... And i don't know why it happens
or what triggers it..
But it is some kind of memory problem.
You can check by pressing F3 right-top corner

 

[chaos_ignitez]

maybe something happening in the background of a specific mod builds up and causes increasing lag

 

[lenscas]

It is caused by a memory leak, ftb can't do anything about it and it is right now something you just have to live with.
As far as I know it get worse if you often switch dimensions,

 

[engel]

I had this bad, then took some random advise and disabled Journal map and enabled Opis instead and my lag went away. No clue if this is a one off thing, but worth a try.

 

[JaRyCu]

You don't have to completely disable JourneyMap, just turn down what it does. I changed mine to minimal settings, only updating the minimap every 10 seconds, and I told it to only map where I am (cave vs overworld), and that really improved performance. I still have to log out if I play for a few hours, but then I log right back in and it's fine.