The iMac I had at work definitely didn't exhibit the IR until it warmed up under normal use. I first noticed the issue while installing applications. (I ignored it at first, hoping it would go away.) If the replacement unit also has IR, I will try to get temperature readings. My ambient office temperature is usually between 73 and 77 degrees (F).
Here is another photo I had taken:
IR of Checkerboard Pattern
Previously posted:
Youtube Video of IR
Test Image
IR of Test Image
Zoom 1
Zoom 2
Here is another photo I had taken:
IR of Checkerboard Pattern
Previously posted:
Youtube Video of IR
Test Image
IR of Test Image
Zoom 1
Zoom 2