You've left out most of the information needed to answer:  what model system?  Are you asking about an external monitor, or the internal display panel of a (presumably XPS) notebook?  And if an external monitor, what model monitor and how is it connected (Thunderbolt, HDMI, etc.)?

i have the up3218k monitor connected via 2 display ports to my desktop pc on windows 11

thank you for your reply

your solution is not helpful and a bit botish altho i appretiate your reply  there are no other monitor options that has 32inch display at 8k 7680x4320[16:9] at 60hz the only other options that have 8k and 60hz or above are larger then 32 inches and there for have a larger space between the pixel density one resaon i bought this model still i would like some support with my options to what can be done about this 10 year old monitor to allow customisable resolutions to be input to the software via official channels or 3rd party software that is safe to use.

yes i dont strech my resolution so black bars are perfect for a true 4:3 res and i already now what the resolution options are as they are the only options to choose from on the nvidia control panel however i am wanting to customise the resolution an option on the nvidia control panel that is greyed out hence why i asked for 3rd party software options or an offical software or update to resolve my issue

other monitors i have handled allow you to input a custom resolution on the nvidia control panel for example if your monitor supports a resolution of 7680x4320[16:9] then it should be able to support a custom input resolution of 5760x4320-[4:3] as there are enough pixels per inch the monitor can display

again thank you for your reply

The bottom line is that you're fishing for an answer that does not exist.  Software cannot control what hardware does not support.

4:3 on a monitor that's designed for 16:9 is either going to have a stretched image or black bars around it.

The resolutions that this monitor can handle are listed in the manual:

https://downloads.dell.com/manuals/all-products/esuprt_electronics_accessories/esuprt_electronics_accessories_monitors/dell-up3218k-monitor_user%27s-guide_en-us.pdf

Since you're convinced of that, try whatever software you were using before.  Either it will work and you can report back, or it'll confirm more more likely outcome -- that you're limited to the resolutions that are built into the design of the control board inside the monitor.

It should pose no risk to the monitor itself, as you'll see either an "unsupported resolution" message or simply a black screen.  Just make sure there's some GPU failsafe you can fall back on in case the settings become locked on the system (or that you have another monitor you know can display the settings you try).

the hardware is not at question here its the software that is there are 3rd party solutions for the same issue but with other monitors that dont utalise 2 display ports to display an output eg my old monitor allowed the customise option so i could input a custom resolution even tho it was not a reccommended option and even older displays you could use a 3rd party software to input a custome resolution that the display can output that is not an option on the nvidia control ect.

the hardware does support resolutions up to 8k but you choices of resolution is limited to what the company as deemed to be hence why 3rd party solutions have become a thing if the hardware can display so many pixels and a resolution up to 8k then a custome resolution can be input into the display as long as it does not exceed the pixels display limitsif i was more techically minded i would simply write my own program that would give me my desired resolution i am not being impossible and its only logical the display can produce 7680x4320[16:9] there for it can also produce 5760x4320-[4:3] as this resolution is lower then the max resolutin and within the pixel density display poramiters

alright i have had abit of a try with the custome resolution utility with no luck and found this forum online explaining that the extension blocks in CRU for the 2 dpi ports are hiding key information and this example is not explaining how to achive custome resolution to my specheres the link https://www.monitortests.com/forum/Thread-What-do-I-need-to-modify-to-add-a-custom-resolution

I have managed to achive a resolution os 2880x2160 with the Scaled Resolution Editor (SRE) https://www.monitortests.com/forum/Forum-Monitors-Video-Cards

however the 5760x4320 is still not achived its seem to achive this have have to send a 2880x2160 down both dp1 and dp2 and also config a 5760x4320 resolution all in the extention block of the Custom Resolution Utility (CRU) and also might have to remove all other data to achive this goal

i have to understand what i am doing to achive this eg with the: pixels, lines, mhz, and in the program itself  i have found by only useing one display port i can see the extention blocks but this is only true for dp1 and not dp2 or both togeather

this seem like a lot of effert only for me to game at 5760x4320 a 4:3 resolution however i do now have access to 2880x2160 but this would be true for any 4k display the monitor only becomes usfull in a 16:9 resolution to take full advantage of the 8k performance i now it is achivable

and someday it will be 16k as that is the limited possablety to date and yet everyone is still all going on about 1080p 240hz madness wich is really holding resolution back.