I have faced the same problem in UE 4.20.3.
You may avoid the problem with following option in DefaultEngine.ini file.
[/Script/Engine.RendererSettings]
…
r.DefaultBackBufferPixelFormat=0
The default value is 4 which makes the engine to create default back buffers with PF_R10G10B10A2 format.
But I’ve figured out the format in fullscreen mode is not supported well on some GPUs by testing with DirectX 11 sample program.
When I ran BasicHLSL11 sample program with the corresponding pixel format of DXGI, I could see the same situation just like green flickering screen.
I think the reason is not caused by UE though, I wish Epic guys make some modifications to address the problem by changing policies to select default back buffer pixel format.
Here is the testing computer’s spec.
- Operating System: Windows 10 Pro 64-bit (10.0, Build 17763) (17763.rs5_release.180914-1434)
- Processor: Intel(R) Core™ i7-6700 CPU @ 3.40GHz (8 CPUs), ~3.4GHz
- Memory: 32768MB RAM
- Card name: NVIDIA GeForce GTX 1060 3GB
- Current Mode: 2560 x 1080 (32 bit) (60Hz)
- Display Color Space: DXGI_COLOR_SPACE_RGB_FULL_G22_NONE_P709
I hope this helps you.