I still am the lone Windows 8 was a better GUI guy, but Microsoft gave what people wanted in 10. I have not had your problem with 4k and 1080p mine plays nice

I still am the lone Windows 8 was a better GUI guy, but Microsoft gave what people wanted in 10. I have not had your problem with 4k and 1080p mine plays nice with each other. I think it might be a driver issue on your graphics card.