Ram usage raises constantly till game crashes (up to 6gigs)

[Klotaucher]

Hey guys I have a problem for like a week now. I´m playing Hexxit on a server with a few friends and in the first days everything was fine. But like I said since last week the game keeps crashing after some time. I figuered out that java uses WAY too much ram. I allowed the launcher to use 3 gigs. It starts with 3 gigs but after a few seconds it begins ro rise .... till the game crashes. Minecraft is the only game I have this proplem with. Destiny, Witcher 3, Doom, BF1 PUPG and CSGO work just fine. So it has to be a problem with Java right? 

Things I´ve tryed : Java down/upgrade/reinstall ; graphics driver down/upgrade/reinstall ; restarting computer ; deleting Hexxit and Technic launcher ; changing texture packs ; virus scan ; priority controll ; raising the allowed amount of ram for java to 4gigs (it just ignores that btw) ; 

The strange thing is when I press F3 in hexxit it says that it uses like 700mb-1000mb not even close to the amount java seems to ocupie in the task manager 

RIG: i5 4670k(oc); GTX 1060 6gb msi gaming plus(oc); 8GB kingston ddr3; msi mainboard (freshley flashed bios).

PS.: sry for any typos im not a native speaker ^^ and pls dont kill me if this is the wrong "thread" I´ts my first time posting ANYTHING in a forum normally asking google helps, so dont think that I haven´t googled that took me like 4 hours! 

thanks in advance