Help with rig power?

So I was watching a video and for my second rig I was planning on getting one of the 8 GPU riserless rigs mobos. But the video explained it for Ethereum mining. I was wondering what kind of power setup I should have for an 8 GPU rig. I was kinda wanting to expand into using server PSUs but I never have so I don’t know much about them. Any help would be appreciated!