Question Choosing default GPU- AMD and Nvidia

[ObaiSukar]

Hello Guys,
I have a computer that has 2 GPUs

GPU0 is Nvidia Geforce GTX 750Ti
GPU1 is AMD Radeon RX 570 Series

When I try to swap them physically on the motherboard, only one card works (AMD Radeon)
I want to be able to use one for display (Nvidia) since it has 4K output for my big screen but be able to use the AMD for Processing for Games. I noticed not all games let you choose which GPU to choose for processing. How do you change the default GPU for Gaming graphics?

 

[helpstar]

Remove the GTX750TI, or why do you think the nvidia card is better for 4k?

Is it a laptop? Which brand and model is it?