I am looking for a UPS for a Late 2012 27-inch Core i7 and I see recommendations for a CP850AVRLCD from the CyberPower Intelligent LCD Series. Is this sufficient? I worry that the flickering I was experiencing is from the worsening quality of power from the grid. Apple skipped the Late 2012 27-inch Core i7 power consumption rating. So I am stating the max power consumption from the 2011 model (200 W) and 2013 model (229 W). Goal: Clean power to the iMac, battery power for at least 10 mins and auto shutdown on the last minute of battery life.