I have my 2015 5k iMac with a 2009 1440p iMac as the second monitor. The 2007 iMac looks completely yellowed by comparison, the whites are not nearly as white as the 5k. I tried the expert mode calibration settings but could not get the whites to come anywhere close to the 5k iMac. Has anyone been able to successfully calibrate the two monitors to look good next to eachother? I know the 5k is naturally a better monitor, but I wouldn't think that it would blow the old one away so much. The old screen seriously looks like a yellowed antique next to it.