https://www.asus.com/us/Motherboards/PRIME-Z390-A/Do you have a gpu? What exact motherboard, there are many ASUS Z390 boards?
Oh I see. How do I use both 4K monitors? What GPU or type of GPU do I need?Ok the motherboard supports
Supports HDMI with max. resolution 4096 x 2160 @ 30 Hz
Supports DisplayPort 1.2 with max. resolution 4096 x 2304 @ 60 Hz
However the max resolution of the integrated graphics on the 9700k is 4096x2304. So you might be able to duplicate across 2 4k screens but you wont be able to extend across 2.
Its not something I have researched but from a quick search to support that resolution I needed to look at GTX 1050's minimum. This has HDMI, Display Port and DVI so you can use 2 of these. There might be better options but will let others suggest.Oh I see. How do I use both 4K monitors? What GPU or type of GPU do I need?