Low FPS with RTX

Hi, I have trouble with RTX. During the game my fps drop to 30(2 screenshot) but at some moments fps becomes ~60(1 screenshot). Previously, this was not even on 24 RTX chunks.

My setup:

CPU - I5-4460(4 cores and 3.6GHz)

GPU - RTX 2060

RAM - 16Gb 1600 mHz