Make sure you test your iMac as soon as you get it. Here is the test: http://www.marco.org/rmbp-irtest.html Please run this test and post your results. If you have Image Retention, it is not normal as Apple would have you believe. Only faulty LCDs have it. These displays are made by LG, and have a bad track record as being seen over on the MBPr threads. Please test your iMac as soon as you get it and return it to Apple if you have IR. The IR will get worse over time. Do not accept a faulty LCD and do not accept repairs.