I picked up a Dell S2415H 24" Monitor from staples for my parents 2012 mac mini computer. Im running yosemite I hooked it up via the hdmi port to carry the sound through one wire. Randomly the dell monitor will quickly go black and come back on. Almost seems like its using some kind of energy saving thing. I hooked it up to another mac mini I had, and it did the same thing. An hour with dell and they had me run a monitor test and find no problems. Any ideas what it might be? Maybe something set wrong on the mac mini display settings? Maybe I need to use the thunderbolt display port and an adapter instead? Its driving me crazy.