Help, please. Strange lags. Need help. (Minecraft)

Minecraft is kind of weird. If I want to pass any map minecraft, at first nothing, but then all the lag, chests, stove open for a long time, the damage is impossible. Fps no lag, Internet is not needed. Happens on all maps(before such was not)
My sistemnik:
percents - intel core i5 7400
video card - geforce gtx 1050ti(manufacturing Palit)
memory - only 16GB allocated to minecraft 3GB.
The number of RAM for minecraft changed fps no lag, the file location of the game changed.
Nothing helps. Maybe someone of you had it? Corrected you? How?