Since I wanted bereiben 3 monitors at a GTX680, I thought that HDMI is sufficient for the third monitor. Unfortunately, under HDMI to adjust the picture too bright. The unfortunately by the graphics card that has not resulted in identical monitor settings and calibration with the Spyder to the desired success. Hab then browsed the web and little rausgelesen that the GPU under HDMI provides a "TV" and deshalbt values other than under DVI takes. A DP cable should be the solution. Thanks to the quick delivery, the desired DP cable was quick for me. HDMI out, connected via display port and now the monitor as his two "brothers" works exactly the same.
I'm very satisfied and now I have a homogenous visual impression of all 3 monitors!