Hi, I am having problems with my iMac 27 running a 2nd monitor. Just bought a Iiyama ProLite XB2779QS-S1 27" which has a max resolution 2560 x 1440. I connected it using the mini display port (thunderbolt) to HDMI adapter which I already had but the monitor will only display in 1080p (1920 x 1080). I googled the problem to find an answer which said I need to connect the monitor using the display port so I purchased the iWantit IMDHDD13 Mini DisplayPort Adapter which is a 3 in 1 adapter and used the display port cable that came with the monitor. The problem I now have is the monitor is detected but is just black. If I make any changes it flashes momentarily and then goes black again. If anyone has any ideas they would be greatly appreciated.