I have an odd issue, and I was wondering if anyone has a solution. In OSX, on a 15" late 2013 rmbp with 750M, if a monitor, using displayport, is plugged into the laptop, the computer will not sleep for more than 5 seconds. After about 5 seconds, it wakes up. If i use a DVI adapter on the same monitor, this issue does not occur. OSX is running all the latest patches, and the same issue does not occur in bootcamp on the same computer (Windows 8.1). The monitor is a Dell U2412M.