Try this perfomance fix (made by Vizra)

[Dante]

Under the file ‘settings_common.ini’ ,. Found in your local game files (for steam this is under C:\Program Files (x86)\Steam\steamapps\common\Warhammer 40,000 DARKTIDE\bundle\application_settings). I changed the following values:

mesh_streamer_settings = {
disable = false
eviction_timeout = 5
frame_time_budget = 1
io_buffer_budget = 10240
limit = 768


streaming_buffer_size = 128
streaming_max_open_streams = 64
streaming_texture_pool_size = 512
surface_properties = "application_settings/global"
texture_streamer_settings = {
streaming_buffer_size = 128
streaming_texture_pool_size = 1024

Under the file win32_settings.ini (Found under | C:\Program Files (x86)\Steam\steamapps\common\Warhammer 40,000 DARKTIDE\bundle\application_settings) change the following value called ‘fullscreen’ from false to true:

renderer = {
adapter_index = 0
aspect_ratio = -1
d3d_debug = false
d3d_gpu_validation = false
dlss_logging = 0
dred_pagefault = true
fullscreen = true
fullscreen_output = 0
gpu_crash_dumps = false
ray_tracing = true
screen_resolution = [ 1920 1080]
}
After saving, set these files to read only. Now i have more stable fps on 7800xt.
All credits to Vizra.

[sAIN`t-9]

Nothing improved for me :<