The refreshrate of your monitor is fixed and cannot be overclocked.
You can force a different refreshrate through the drivers, but what this does is forcing more or fewer frames to the display than it can handle, which results in a compromise. As the display doesn't want to lose any frames it will fill the missing frames with frames that were sent earlier, causing weird glitches in the process.
An LCD monitor usually supports 30hz and 60 hz, and some have an odd 59hz as "compromise" to still show content well. It is possible that with any odd refreshrate, the monitor defaults back to the 30hz one which will look worse in any case. You can test this by setting it to 30hz and compare it to the other bad ones.
Refreshrates were interesting with CRT monitors, where the higher you had it, the more "still" the image could appear, but this is no longer the case with LCD monitors.
Do note that the LCD refreshrate and in-game FPS are related, which is why enabling V-Sync locks the FPS to 60 so they are in sync with what the display is capable of, but disabling V-Sync in game will usually allow to set a higher FPS and it will still look good compared to changing the hz of your monitor. So if your objective is to alter the hz of your monitor and have v-sync on with a higher framerate, forget about it, it won't work. Just disable v-sync and find out how to set the max_fps in that game. Usually its a matter of a console command or editing your config file.
What were you hoping to gain by this? It would appear to be some bizarre XY Problem If the answer has anything to do with making a game 'look better' then it's definitely an XY.
– Tetsujin – 2017-01-14T11:28:53.837