I have set up my first mining rig. Very simple cheap rig as a test run. The mother board I used has an HDMI out which I used to set up windows etc. When I placed my first GPU into the board and booted up nothing came out of the board HDMI anylonger. Hmm. Makes sense I guess. So I put the HDMI into one of the GPU cards and i could see the computer again.
A few questions here...

Where do most people get their video out from their rig? on the board? a single GPU card? Which card? Does it make a difference?

Does it slow down the mining on the card to have an active HDMI powering a 4k monitor coming out of it? It has to right?

Does it help the GPU out for mining if the HDMI is unplugged from the GPU after mining has commenced? If so is there a difference from this than just turning off the monitor/tv?

Thanks for any help

Healimonster