Hello, I have a late 2008 MacBook upgraded with 4 GB memory and a good SSD. I used to have a 27 inches secondary display in QHD resolution (2560x1440) over a mini displayport to displayport cable. I just bought a 28 inches 4K monitor (3840x2160) but it is not supported by the MacBook GPU (GeForce 9400M): the screen goes black, but MacOS still keep it as a valid display. Thus I can't rollback to a supported WHQ resolution (the window is on the black screen I think). Do you know any way to use this new monitor as a secondary display at a WHQ resolution? Or should I simply buy a new Mac? Thanks in advance.