Question Overclocking my monitor

[sodium.in.toilet]

I "overclocked" my 60hz monitor to 75. I went to nvidia control panel, made a custom resolution, didnt change anything except for the refresh rate, ran the test and it worked so I selected it and now I can run my games in 75hz. The problem is that it runs like crap. Looks more like 30fps but I have v sync turned on and it says I'm getting 75fps. I played gta story mode to compare 60 and 75 since it's a pretty low requirement game and 60 runs way smoother. Do I need to change more settings? I'm using an old flatscreen tv 1080p hdmi. My GPU is msi gtx 1060 6gb so I think it should be able to do above 60hz through the hdmi.

 

[SteveRX4]

PC Specs?
Monitor make and model?
If you put the monitor back to 60Hz, does it run better?
If so, then don't "overclock" it.

 

[sodium.in.toilet]

Msi x299 raider motherboard
I5 7640x overclocked to 4.8ghz
Msi gaming x 1060 6gb overclocked to 2100mhz
24gb ddr4 2400mhz
Raid0 hard drives

The monitor is Sanyo LCD model number DP42D24-00

I think its 43 inches, but 1080p 60hz. It's pretty old probably atleast 5 years. I used to use it on my ps4 but I got a pc with the intention of getting a new better monitor but this one seems to work fine so I've stuck with it. Just not overclocking it is always an option I just want to know how I can make it work in 75hz. I've never messed with anything over 60 so I'm interested to try it out because people say 75 makes a pretty big difference.

 

[SteveRX4]

It looks like you cannot make it run at a 75Hz refresh rate.

Did you do it like this -https://www.youtube.com/watch?v=jUwwtNIRndo?

 

[sodium.in.toilet]

Yes thats the exact video I watched. My games recognize the 75hz and everything, It just runs worse than 60hz does and i dont understand why. im going to try to back it off alittle.