Game keep crashing time to time and fps drop on water maps

I get random crashing around midgame (age 2 - age 3) once in every 30 matches. No error number/any information given after crash.
Also i heard from my mate, that there is huge fps drop on water maps. Never had it before latest patch (9369), now its unplayble for me on water maps aswell - drops from 70-90fps to 10 when i look at the water space.

My pc drops frames during in an in-game camera viewing sea or water areas, too.
So I planned main memory enhancements (already replaced drives for fast loadings)
It seemed AoE4 water acts with so-called randomly surface reflections and its(those) opacities in high-level-accurate lighting likely recent movies.
Water in many games is rendered with pre-painted textures and 1-time lighting I think but AoE4 has advanced details.