I've got a base model 27" 2017 iMac - 3.4, 570, 512gb SSD; delivered on the 8/8. When everything in the house is quiet, ie. kids have gone to bed, I can hear the fan quite clearly. Nothing is running and it's at idle, 1200 rpm. Is this normal fan noise? https://www.dropbox.com/s/b6r6kbm79428s9b/2017-08-13 22.38.59.mp4?dl=0 https://www.dropbox.com/s/k2dqhgx0smjconl/2017-08-13 23.29.30.mp4?dl=0 https://www.dropbox.com/s/2rdb26p45yl9m3m/2017-08-13 23.30.14.mp4?dl=0 Thanking in advance for those who listen and comment.