I have an early 2011 Macbook Pro 15" that I connect to a 2010 27" iMac in Target Display mode. When I do this, the iMac display flickers every few seconds and sometimes will even go completely black. I've read online that the solution is to do a SMC reset and PRAM reset. I've done both and still have the flicker. I've hooked up a 2012 Retina Macbook Pro 15" to the same iMac and there is no flicker at all. Works perfectly. It looks like OWC ran into the same issue. You can view video of my exact problem on their YouTube channel. Anyone else had this issue or have any suggestions? Thanks.