I hate to bring up another dreaded image retention issue regarding the iMac, but I like to think my issue is unique in that it only manifests under Windows and not at all on OS X. On OS X (running Yosemite), I have absolutely ZERO IR. I can leave a finder window open for hours, switch to a gray screen and it leaves nothing behind. The IR tests such as the grid test all succeed without any IR present. But whenever I boot into Windows, even if I leave a browser window up for a mere 5 minutes, it causes IR. Also all the icons on the desktop are burned into the screen too under Windows. I have attempted a few things, such as lowering brightness, updating Nvidia graphics drivers, changing resolutions, etc. to no avail. This is extremely PUZZLING to me of why Windows will cause IR and not OS X. Does anyone have a similar problem or have any suggestions of what I can do to get this fixed? I use Windows a lot so it's not like I can get rid of it and use OS X exclusively.