I have similiar problems with rendering like Texture rendering problem on weak PC.
My PC specs:
GTX 660
8gb ram
Windows 10
i5-3570K
I also noticed error spamming in the console:
When I set mat_fullbright to 1, it stopped spamming, but issue is still here.
Maybe that error will help.
My PC specs:
GTX 660

8gb ram
Windows 10
i5-3570K
I also noticed error spamming in the console:
Code:
[Assert] C:\buildworker\citadel_rel_win64\build\src\rendersystem\dx\rendercontextdx11_software.cpp (1460) : AssertMsg Failed in function CRenderContextDx11_SoftwareCommandLists::DispatchComputeShader():
Trying to dispatch compute shader without binding one first!
Maybe that error will help.