Light, Trees, and huge fps drops

Development Rendering
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Hello! I think everyone had the idea to grow a forest in Unreal Engine. I tried that too, and faced a very large fps drop =/

I will try to show in pictures the testing on the example of 10 trees (Starting level, tree created with Speed ​​Tree / 17k triangles)

I used 10 pines to simulate forest, lights are direct/movable

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11920×904 225 KB

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21920×905 414 KB

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31920×906 209 KB

I assumed it was due to the lighting.

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51920×905 458 KB

After short profile Shadow mips test was failed

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61920×799 253 KB

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81920×798 218 KB

Also tests was failed for directional/static light (both, baked and unbaked versions)

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91920×873 256 KB

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101920×865 290 KB

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111920×818 240 KB

It’s really wondering.
My PC: 3060ti/24RAM/i7/ssd

How can I use 10 trees in a scene without performance loss?

Add
kk, bit closer to understand

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Solved.
Sorry for huge post

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You need to be testing properly and using the tools in the engine that are designed to help with what you’re trying to do. For example, you can’t place 10 trees in the same location to test if it can handle 10 trees. The engine also has a foliage system designed to handle large numbers of plants. You should also be using LOD systems

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Nah, pines are deliberately placed in one place to create stress for shadows. Situation when the shadow of one tree falls on the shadow of another in the forest is quite common. This overlap caused the fps drop.
It turned out that shadows were cached by the engine by default. Disabling this cache eliminated this trouble, now fps stable 60 in any camera position

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What is this cache called and where can it be disabled? My FPS dies like this whenever I place trees. If this solves the problem, that would be wonderful.

Like you said not that many trees and they’re pretty low res. Foliage systems and instancing make no difference with the issue mine have.

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