PowerStrip
you have to go into the custom resolutions sections
i was able to set my Samsung 955DF to 12x9 @ 80hz [it would be 75hz otherwise] . . . the specs allow 12x10 @ 79hz . . . so i pushed it a little
and PS takes a little getting used to . . .plus you can damage your monitor if you run it too far out of range [but not so far out it doesn't display]
generally i don't use it as i game at 11x8 @ 85hz