Question all in one desktop display

[xfr0stx]

whenever I change res it works fine but sometimes this problem occurs and I tried overclocking monitor to 75 hertz 640x480 res this happens dont know why any fixes?

https://imgur.com/a/95v876C

View: https://imgur.com/a/95v876C

 

[punkncat]

I am not sure I am understanding your problem.

You are saying it will change native resolution just fine?

When you attempt to OC it to 75hz it changes itself to 640x480?


I am not sure I can help, really. My current desktop monitor will OC to 75 even though it's a 60hz monitor, and it seems to work well for most desktop apps. It will not operate properly in most games at that setting.
Is 75hz @ (desired resolution) available as a supported mode, or are you forcing it in control software?

 

[xfr0stx]

How do I know if it is supported im using the cru to make it 75 hz.
I added a 640x480 75 hz rez but when I apply it I get this error