I set my monitor to 144hz and now I cant go back

Hi,

finally it took me a lot of time but I managed to make Sierra work with my pascal GPU. In the display settings I tried to set the refresh rate to 144hz (since my monitor supports it) and the screen crashed (RGB noise all over the screen). The only fix I found is to use the HDMI port (since my monitor only support 144hz on DVI-D port). So now I have my screen plugged both using HDMI and DVI-D, and my hackintosh will detect a dual setup. It works, but it's not great. I can't edit anymore the rate I tried with my pseudo monitor setup but both are set to 60hz.

Thanks in advance