Cannot run a custom resolution natively

[AlmostEasy]

So I have a 16:10 monitor with a native resolution of 1680x1050.

I would like to lower that resolution while maintaining the aspect ratio of 16:10

The one that made sense was 1280x800 which was already listed by default as a resolution by windows. But for some reason it's not running natively.
My monitor reports an actual resolution of 1280x960(4:3) which means it's being scaled and not running natively. (display scaling?)

In AMD Adrenalin Panel I have made sure that GPU-Scaling is set to off.
If I turn it on it gets even worse and scales at an even higher resolution (the monitor's native res specifically)

All I want is to run a low 16:10 resolution natively. Too much to ask?

[ToastyX]

If the monitor doesn't have 1280x800 in the EDID, it will scale to the next highest resolution. Have you tried adding 1280x800 with CRU?