Just received my new iMac (i9 w/580x)...and am surprised on how often and for how long the fan runs. It's not necessarily the level of noise (I am coming from a 2010 iMac that was on its last leg), but how often/long it runs. I can understand it kicking in at times when my wife is in Lightroom or Photoshop, doing exports, etc...but it seems to be running quite often (and for more than just a few secs) when simply on the internet and other "simple" tasks (been running the last 5 mins while all I have been doing is looking at this forum). Is this normal for this machine? Not sure I really want to mess around with sending it back (removing everything, etc), but worried this may get annoying after a while.