From TFTCentral it looks like "Custom Color" mode is sRGB. Can you confirm ? Also any plans to allow DCI-P3 mode in Custom Color and Game1/2/3 modes ?

https://tftcentral.co.uk/reviews/dell-alienware-aw2725df

Custom mode should be maximum gamut, not limited to a specific Color Space. 

Thanks. If that is the case is there anywhere I can verify it ? Windows ? Nvidia control panel ?

To verify actual color space and calibration accuracy will require a hardware instrument and software. More here

This is not cheap and often exceeds the value of the monitor.

So a better option is to look at reputable monitor testing sites and read what they measured.

For some monitors a factory calibration report is included, for certain color spaces.

Can you explain what you mean by "maximum gamut" ? Do you mean "Custom Color" is DCI-P3 as it covers more of the color gamut than sRGB ?

DCI-P3 only available on creator mode and it has a really bad green tint and no way to fix it either , we need a firmware update :)

@iiTzDarkness​ Maximum gamut is the maximum colors that can be reproduced by the display panel. It's visually represented by a triangle inside the RGB color axis.

Color spaces like sRGB, DCI-P3 are standardized color gamuts that ideally have to fit within the color gamut of the display panel. This is not always the case and you might see things like "covers 99% of sRGB, or 128% of sRGB as not all panels are capable of reproducing the full gamut (range) of colors needed for that specific color space.

The colors spaces are often called "clamped" because they limit the display color reproduction to the selected gamut rather than "unclamped" full gamut.

Gamut