I can't a a custom resolution

Hello, today I tried to add a custom resolution though the CustomModeApp in System32 to 1280x960 but, as of changing it I received this message: "The custom resolution exceeds the maximum bandwidth capacity". I know that my laptop's monitor can support higher then that, and lower too. Why is is that I can't change it? I would like to be able to add this one custom to my laptop.

Thanks,

Charles.