Your system might have 8GB, but that will be split with the integrated graphics card.
As the runlog says
INISettings:: DetermineVRAM dedicatedVideoMemory 128MB dedicatedSystemMemory 0MB sharedSystemMemory 4038MB vendorID 8086 deviceID 5916
The value for video memory is rather low. So the graphics card will struggle. I am also somewhat concerned by that the fact that the shared memory value is lower than it should be.
Here is an article describing how to check your VRAM and how to increase it.