Hello, thank you for your patience while we were waiting for an update from the engineering team.   To achieve 500 nits, SDR mode needs to be selected.   This panel is HDR400 compliant hence when HDR mode is selected, the luminance will be 400 nits.
I purchased new XPS Laptop around 4 weeks ago. UHD+/4K Resolution (3840 x2400) with Touchscreen. Running Win 11. Noticed that on Advanced Display Adaptop it only showed 400 nits opposed to the 500 it should have for this screen. Running Display HDR Test from MS Store as well confirmed these lower nits. Dell opened a case for this and as well replaced the LCD Screen as well as the Motherboard onsite under Premium Support. After running further tests it still only showed 400 nits. Did anyone have come across this and can tell me if this is software or hardware related? In addition if anyone has similar laptop with specs can you confirm that running Display HDR Test shows 500 nits? Thanks
Dell XPS 13 9310 UHD/4K (3840x 2400) only showing 400nits