google: hdmi capacity
regular hdmi cables will not suffice.
you’ll want hdmi 2.0 cables which support up to 4K @ 60 fps.
hdmi 2.1, on the other hand, promises 4K @ 120fps and 8K @ 60fps
Of course... except that I don’t need 4k 60 fps on all card outputs as I’m not gaming and the card it looks like I’m getting* (just put in an offer on eBay) MAY only do 4k on ONE output, the rest 2k or lower. (Seems to be some debate about that.) No matter, I only have one 4k display.
Nonetheless I found a 4k 60 Hz cable in my “Video Cables” box, so, assuming it meets it’s description, I should be good to go. And Amazon is running some very good specials, too...