Setting a custom PBP resolution using CRU

[Rajveer]

I have an Acer X34GS (native 3440x1440 resolution) which supports PBP, but doesn't have 1720x1440 as a supported resolution in it's EDID. I'm trying to add this resolution.

What I've tried:
I have a Nvidia card, and so I've added a custom resolution in Nvidia Control Panel. This gives me a Desktop Resolution of 1720x1440, but an Active Signal Resolution of 3440x1440.

This isn't a problem if I set scaling mode in Nvidia Control Panel to No Scaling, and then set my monitor's PBP mode to Full instead of Aspect Ratio - the 1720x1440 image stretches over to 3440x1440, and then the monitor forces it to half the screen, essentially unstretching it.

However, I would like to have an actual native resolution of 1720x1440, so that I can keep my monitor in Aspect Ratio mode (so I can use it with my Switch keeping it in 16:9, and also because the stretch-and-unstretch makes text look thicker).

FWIW, I can achieve this using SwitchResX on macOS, and so I know that a native 1720x1440 resolution does work.

Using CRU
I've tried adding a new resolution in the Detailed Resolutions part of CRU, but it doesn't appear in Nvidia Control Panel nor in Windows display settings. Any help would be appreciated!

[ToastyX]

Is there a default extension block? You can't have a default extension block with NVIDIA. Read the part about extension blocks.

[Rajveer]

(10-24-2021 04:43 PM)ToastyX Wrote:  Is there a default extension block? You can't have a default extension block with NVIDIA. Read the part about extension blocks.

Thank you for pointing that out - there is a default extension block, and when deleting it I am able to now see my custom resolution

One thing I've noticed though is that when deleting the default extension block, the range of refresh rates becomes capped at 100Hz (the monitor supports up to 180Hz). I can add higher rates manually to a resolution, but I'm wondering if I can add this custom resolution without negatively affecting refresh rates or anything else?

For reference, here are images showing refresh rates with and without the default extension block:

With:
   

Without:
   

And when adding a custom resolution added supporting 180Hz, here are images showing the range of refresh rates for standard and the custom resolution:

Standard res:
   

Custom res:
   

[ToastyX]

You have to add 180 Hz back in manually because it's in the extension block that NVIDIA's driver couldn't read. There should be no issues with that.