DSR/Downsampling at 144Hz

Hi all,

I recently purchased a 2k (2560x1440) 144 Hz Gsycn compatible monitor (Lenovo Legion Y27q-20) which is connected to my GTX 1080 via DP. I have been desperately trying to get 4K DSR to work at 144 Hz in the past few days to no avail.

Without DSR or custom resolutions, all my games and Windows see a set of phantom 2560x1600 and 4k resolutions at 50, 59 and 60 Hz. When I enable DSR in Nvidia's control panel, again only those resolutions are seen and any other resolution that I add is only seen at 60 Hz and below. If I disable DSR but add a custom resolution of 4k at any refresh rate (including 144 Hz) using the control panel, then Windows can see that resolution and Hz, but none of the multiple games I tried do and the games again only see the above phantom resolution and refresh rates. I have tried getting rid of those phantom resolutions using CRU, but I cannot see them anywhere to remove them. I believe the phantom resolutions come from here:



Does anyone have any idea how I can remove or disable those resolutions, or how I can get 4k 144 Hz DSR working in some other way?

Previously I used a standard 1080p monitor that I had overclocked to 80 Hz that was connected to the same GPU via HDMI and 4k DSR worked just fine at 80 Hz. I guess the new monitor being connected via DP could also have something to do with this problem but I need to use DP because of Gsync.

P.S. My OS is Windows 10 x64 1909 and I am on Nvidia driver v451.67. Also I have already tried DDUing the driver which made no difference.

 

i don't have this problem.

 

That is fantastic, my friend; thank you for your valuable input.

 

I have a GTX 1080 Ti and a 27" 165 Hz ASUS ROG Swift PG279Q G-SYNC display (connected via DisplayPort).

DSR 1440p@4K and 165 Hz works fine for me but my DSR resolutions show differently to you. They are listed in the NVIDIA control panel > Resolution section like this (and separate from the other default resolution which show under the [PC] section):

[Dynamic Super Resolution]
5120x2880 (4.00x)
4434x2494 (3.00x)
3840x2160 (2.25x)
3620x2036 (2.00x)
3413x1920 (1.78x)

... and so on. This list depends on which scaling factors you have selecting in the Global NVIDIA profile and I can just select them (sometimes with several different refresh rates per resolution) in the games themselves.

I have a monitor driver installed... not sure if that makes a different from, say, using the Generic PnP driver that Windows otherwise uses.

Sorry I can't be more help. Not to insult your intelligence or anything but you have checked the DSR factors in the NVIDIA Global profile and clicked on Apply as this is what 'activates' the DSR resolutions?

 

@Darren Hodgson This is how the DSR resolutions look in my case:




As you can see, nothing above 60 Hz is exposed and can be chosen for the DSR resolutions. I will try installing the monitor driver to see if it changes anything.

 

well it looks like you're using multipliers of your 4k resolution and you don't have a device on either end that can do 10bpc 120/140 at the native resolution in the first place.

 

Yeah looks like your DSR resolutions are based off 4K so possibly one of your custom resolutions.

DSR should scale from your native res. 2560x1440.

Delete all custom res. and disable DSR, reboot, enable DSR.

 

You described WQHD 2560x1440 as a 2k screen when that is actually 2048x1080 why ?

 

You wont get 120 htz at 4k to run unless you use hdmi 2.1 with a nvidia titan or wait for the next display port.
best advice i can give is try this.
https://custom-resolution-utility.en.lo4d.com/windows

 

Native resolution is 2k and works just fine up to 165 Hz (I initially said my monitor is 144 Hz but it is actually 165 Hz). I just don't understand where those phantom Ultra HD resolutions that Nvidia's driver is seeing are coming from.

Is the 2x DSR supposed to be 2x height and 2x width or 2x total number of pixels? Enabling DSR automatically disables custom resolutions and the first time I tried it, I had no custom resolutions added. Moreover, I cannot delete custom resolutions added using the control panel in any way, unless I do a whole clean install of the driver. Seems to be a wide-spread issue:

https://www.nvidia.com/en-us/geforce/forums/discover/159685/cant-delete-custom-resolutions/
https://www.nvidia.com/en-us/geforce/forums/discover/132138/how-do-i-delete-a-custom-resolution/

That is not a problem with DSR since the output is downscaled to 2k before being sent to the monitor, and what goes through the DP port is 2k 144/165 Hz.

Edit: Indeed it seems 2x DSR is supposed to be 2x number of pixels and for some reason, Nvidia's driver is applying the DSR factors to the phantom "Ultra HD" 4k 60 Hz resolution it is reading from somewhere which my monitor doesn't even support... At the end of the day it seems it all comes down to somehow getting rid of those resolutions. I do not seem to be able to see those resolutions anywhere in CRU, though.

 

you should have the same Hz as native resolution



with 10bit


you use some cheap DisplayPort cable?

 

@GiveMe Not really, I am using the cable that came with the monitor. You do not have a phantom 4k 60 Hz resolution under the "Ultra HD, HD, SD" section like me. In my case, it seems the DSR factors are being applied to that phantom resolution instead of the native 2k 144 Hz/165 Hz and hence, 2x DSR becomes 5431x3055 instead of 3840x2160. I believe you have the LG 27GL850 27'' monitor, right? My monitor has the exact same panel, it is just factory-overclocked to 165 Hz and has gone through some contrast tweaking. I also came across this 2-year-old post on Nvidia's forum with the exact same problem:

https://www.nvidia.com/en-us/geforce/forums/discover/268539/new-resolutions-in-list-/

 

the cable that comes with Monitor is usually crap, i switched mine to because with G-Sync i had horrible lags with the default DP Cable


You mean that?


still 144hz

 

he means the ultra hd/hd/sd section that has resolutions it should not.

Fill it out: https://forms.gle/kJ9Bqcaicvjb82SdA

How to save a DispDiag log file:
https://nvidia.custhelp.com/app/answers/detail/a_id/3468/~/how-to-save-a-dispdiag-log-file

dispdiag goes to driverfeedback@nvidia.com

 

@GiveMe Please check the screenshot in my first post. The driver is seeing some phantom 4k resolution under the "Ultra-HD, HD, SD" section in my case and DSR is scaling from that resolution instead of the native 2k resolution, even though the driver detects the 2k resolution as the native resolution. Since that phantom resolution only works up to 60 Hz, the DSR resolutions consequently also only work up to 60 Hz. Either way, with a tip from ToastyX, CRU's developer, I managed to completely remove the resolutions under the "Ultra-HD, HD, SD" section by removing the "TV Resolutions" from the CEA-861 extension block, and completely removing the "Default extension block" that come after it. After this, DSR scaling works correctly from the 2k resolution and the 60+ refresh rates also become available for those resolutions. Though apparently the overclocked 165 Hz refresh rate is in that "Default extension block" extension block and gets removed by removing that block; I will see if I can restore it manually.



@Astyanax, I will submit a driver feedback to Nvidia nonetheless; not sure how much they would care, though.

 

sems i miss understand it first but using DDU should restore everything back to normal.

Those Custom res. are probably unknown for the driver, so it just uses 60Hz
still wonder why it overwrites DSR resolution with 60Hz as well, probably a bug

 

Okay, I finally got it to work. For future reference, on this particular monitor, it is required to delete the "Default extension block" shown in my previous screenshot using CRU, and also delete the TV resolutions from the CEA-861 block, and then add a new Display ID in the CEA-861 block for 2k 165 Hz using the settings described int his page:

https://motherbear.home.blog/2019/12/10/lenovo-legion-y27q-20-black-screen-fix/

Make sure NOT to delete the whole CEA-861 block as described there or else you will lose HDR; just add the 2k 165 Hz to the existing CEA-861 block.

Thanks to everyone involved in this thread and CRU's developer for their help and comments.

 

I know this is an older post, but how were you able to add that resolution with the 165 hz refresh rate? When I try it is redded out and unable to save. And also, it is listed as CTA-861 for me on CRU.

 

The issue here is DisplayPort 1.4 on the GTX 1080... it's not going to support 4K @ 144Hz 10bit.
https://en.wikipedia.org/wiki/DisplayPort#1.4

DisplayPort 1.4 is HBR3 transfer mode which tops out at 4K@60Hz for 10bit. If you drop down to 8bit color it looks like you could do 4K@120Hz.

 

DSR downsamples.