Custom Resolution Utility (CRU)

[kalamaike]

(06-30-2025 07:03 PM)ToastyX Wrote:  Windows doesn't have any concept of aspect ratios and only supports square pixels, so the only way I can think of is to add 720x576p @ 50 Hz and set the GPU scaling option to stretched in Intel's control panel and hope that it will scale 720x576p to 1440x576i. 1440x576i @ 50 Hz would need to be the first detailed resolution to make it native.

Really 576i is supposed to be double-clocked so each pixel is repeated twice, but the EDID standard doesn't have a way to specify double clocking. You can also try adding 576i as a TV resolution by choosing "Other resolution" and entering code 21. I didn't include that because AMD and NVIDIA ignore it, but maybe Intel will listen to it and double clock it.

Aaahhh! TV resolution 21 was exactly what i needed. That was admittedly my plan from the start but i couldn't find a list of the resolution codes anywhere online so i just forgot about the idea. thank you so much i really appreciate it

[French Toast]

Hello everyone,
I have been dealing with this problem for so long, My 144hz monitor is connected to 144hz laptop via hdmi 2.0 since the beginig there have only been 2 options 120hz and 60 hz so i downloaded cru and now the max is 134 i cannot put it a hertz higher for it to work if someone could please help me i would be very greatful.

[ToastyX]

(07-01-2025 08:54 PM)French Toast Wrote:  Hello everyone,
I have been dealing with this problem for so long, My 144hz monitor is connected to 144hz laptop via hdmi 2.0 since the beginig there have only been 2 options 120hz and 60 hz so i downloaded cru and now the max is 134 i cannot put it a hertz higher for it to work if someone could please help me i would be very greatful.

You need to be more specific. 144 Hz at what resolution? What monitor? What laptop? Do you know what GPU the laptop has? Are you sure it's HDMI 2.0? Did you read about the pixel clock limits in the first post?

[fandangos]

Hi ToastyX,

I'm trying to create an edid bin file from my LG OLED C3 (4k) with a custom resolution of 3840 x 1800 @ 120hz. I want to port it to Wayland since I'm using hyprland on linux and unlike x11, it doesn't support custom resolutions.

Said that, 3840x1800 is just 4k letter boxed for ultrawide, well within hdmi 2.1 bandwidth.

I can't find where should I add it. The only place I could add this resolution as in Detailed Resolutions in the first screen, first box but I was only allowed to set it at 60hz.
Nvidia Control Panel now shows it as 60hz and 100hz but not 120hz.

Where should I add this resolution?

[Kaldaien]

Problems exporting EDIDs containing more than 256-bytes.

It has come to my attention that CRU cannot correctly deal with multi-page EDID extracted through NvAPI. When attempting to export the EDID for my Dell AW3423DW, the EDID is truncated to 256-bytes. In actuality, the display's EDID is 384-bytes.

Sadly, CRU's build environment is not something I can duplicate, so I'm unable to directly contribute a fix for this problem. However, I can provide the code that Special K uses to successfully read the display's EDID in its entirety.

https://github.com/SpecialKO/SpecialK/bl...4201-L4284

---

After reading the API documentation for NvAPI_GPU_GetEDID (...) v3, and this random Reddit post (rofl) I came to the conclusion that 32 KiB worth of buffer should be allocated (no spec was cited for this, so who knows whether it is valid) and then got to work looping through repeated calls to NvAPI_GPU_GetEDID (...).

A couple of key differences between my implementation and what is currently on GitHub:

1. Special K verifies that the monotonic increasing edidId counter is the same for all blocks read and restarts the read-back from 0 (as described by NV) if it changes between 256-byte reads.
2. Special K persistently stores the value of sizeofEDID.
   

Bullet-point #1 is important; without it I would randomly encounter EDID checksum failures.

I am very confused how CRU knows where the end of EDID is when it discards sizeofEDID after calling NvAPI_GPU_GetEDID (...). It is impossible to write the correct number of bytes to dumped .bin files if you just toss it out

[ToastyX]

(07-08-2025 06:04 PM)Kaldaien Wrote:  It has come to my attention that CRU cannot correctly deal with multi-page EDID extracted through NvAPI. When attempting to export the EDID for my Dell AW3423DW, the EDID is truncated to 256-bytes. In actuality, the display's EDID is 384-bytes.

This shouldn't be the case with CRU 1.5.2/1.5.3. Are you using the latest version? Older versions wouldn't read more than 256 bytes because NVAPI wouldn't return more than 256 bytes when using an output ID instead of a display ID, which wasn't properly documented in NVAPI's docs.

(07-08-2025 06:04 PM)Kaldaien Wrote:  A couple of key differences between my implementation and what is currently on GitHub:

That is not my github, and that code is very old, long before the fix. The latest code is in the first post. I'm also rewriting CRU from scratch and will have a new method that also works with Intel GPUs.

(07-08-2025 06:04 PM)Kaldaien Wrote:  

• Special K verifies that the monotonic increasing edidId counter is the same for all blocks read and restarts the read-back from 0 (as described by NV) if it changes between 256-byte reads.
  

The EDID normally doesn't change once the connection is established, so it's not normal for the EDID to change mid-read. If the EDID did happen to change, the driver would reprocess the display, which would interrupt the connection and cause the next read to fail anyway.

(07-08-2025 06:04 PM)Kaldaien Wrote:  Bullet-point #1 is important; without it I would randomly encounter EDID checksum failures.

That shouldn't happen at all. That sounds like a connection problem or an issue with the monitor's EEPROM. Each read is 256 bytes, so that would not affect the checksum, which is calculated per 128-byte block.

(07-08-2025 06:04 PM)Kaldaien Wrote:  I am very confused how CRU knows where the end of EDID is when it discards sizeofEDID after calling NvAPI_GPU_GetEDID (...). It is impossible to write the correct number of bytes to dumped .bin files if you just toss it out

NVAPI's sizeofEDID is the size of the buffer, not the complete EDID, so it's never more than 256. CRU calls NvAPI_GPU_GetEDID until it fails and figures out the size later.

[ToastyX]

(07-08-2025 11:08 AM)fandangos Wrote:  Hi ToastyX,

I'm trying to create an edid bin file from my LG OLED C3 (4k) with a custom resolution of 3840 x 1800 @ 120hz. I want to port it to Wayland since I'm using hyprland on linux and unlike x11, it doesn't support custom resolutions.

Said that, 3840x1800 is just 4k letter boxed for ultrawide, well within hdmi 2.1 bandwidth.

I can't find where should I add it. The only place I could add this resolution as in Detailed Resolutions in the first screen, first box but I was only allowed to set it at 60hz.
Nvidia Control Panel now shows it as 60hz and 100hz but not 120hz.

Where should I add this resolution?

You should add it in a DisplayID extension block.

[Nickatron]

I have a problem this tool may not be intended to solve, but it solved it for me once before. Sadly the drive in the computer that I had this working on, had the drive die, and I didnt think it important enough to have backups running, as all it had was its configuration (after the past 6 hours I very much regret that).

I am trying to use CRU to create a custom resolution higher than that of my 1920x1200 PiKVM v4 mini. I believe before, I went on the Wikipedia "list of common resolutions" and found 2304x1440, which I eventually got working and was running for several months on an Intel N95. As I have read on this thread, intel graphics just dont seem to downscale, so I have no clue how I got this working before. I believe it was at least in part with CRU, but it may have been in the intel control panels. If anyone has an idea how to get this working that would be great. I did try the registry edit for "Display1_DownScalingSupported" mentioned in post #7863, but after a reboot didnt notice any changes to any behaviors.

I have an alternative path ahead as well. Same resolutions as above but with an AMD 2200g. This one is seemingly closer to working, as whenever I add a "standard resolution" at or below 1984x1240@60hz, downscaling works great, and windows shows "desktop mode 1984x1240, 60hz" and "active signal mode 1920x1200, 60hz." If I do 2000x1250@60hz, it no longer shows up in windows settings for me to switch to. I assume this has something to do with cable bandwidth, as the CRU limitation for standard resolution in 16:10 is 2288x1430, which would be big enough for my purposes. In "Standard resolution" I am unable to lower the refresh rate, but would be happy to lower it to 50,30, or 25, as the PiKVM only sends at 30FPS with how I have it configured anyhow.
I am unable to replicate the downscaling behavior in the "detailed resolution" slot. I can get resolutions higher than 1984x1240 to appear by lowering the refresh rate to 50hz and 30hz, but when switching to them, windows shows both "desktop mode" and "active signal mode" have switched to the resolution I want to downscale from (OBS was able to record during resolution changes).

It would be great to get the Intel PC working again, as that is the device the SSD died in, but in place of that the AMD system would be great too. I appreciate any assistance!

[Nickatron]

Intel Down scaling (if you dont care about refresh rate)
Even though active resolution is still your monitors resolution, higher resolutions dont seem to appear in the intel graphics command center (beta) which seems to be where you have to change resolution.
For me this does not matter, so I haven't tried to fix it.
Most of my info was taken from this reddit post: https://www.reddit.com/user/Fearless-Sto...tops_with/

1. Not sure if this is necessary, but I still had "Display1_DownScalingSupported" set to 1 based on Post #7863:
"Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000, create/modify a REG_DWORD value called Display1_DownScalingSupported by setting it to 1 and reboot."
2. Open CRU, and in the detailed resolution section select the premade resolution. You may need to reduce your refresh rate if you are going to a high enough resolution, no harm in trying with default refresh rate first, as you just wont see the option. In my case I used 1920x1200@30hz CVT-RB2 Standard. Hit OK on the box.
3. In the Extension blocks section, edit the existing CTA-816, and delete all detailed resolutions and data blocks. Add a new detailed resolution (still inside the extension block) set this to whatever resolution you are trying to downscale from, at the same refresh rate and timing as the resolution you modified above. So in my case I used 2096x1310@30hz CVT-RB2 Standard. Hit OK on all boxes and run restart64.exe.
4. As long as you can still see your screen and it isnt a modern art piece like mine was when I tried 50hz, install from the windows store, and open "intel graphics command center (beta)"
5. In the Display>general tab LOWER your resolution in the graphics command center, to something that allows the "maintain aspect ratio" option to appear in the "scale" dropdown. I just lowered my resolution from 1920x1200 to 1920x1080.
6. With "Maintain aspect ratio" selected, now change the resolution to your created resolution. If your created resolution does not appear here, go back to step 2 and reduce refresh rate.

[French Toast]

(07-02-2025 01:00 AM)ToastyX Wrote:  

(07-01-2025 08:54 PM)French Toast Wrote:  Hello everyone,
I have been dealing with this problem for so long, My 144hz monitor is connected to 144hz laptop via hdmi 2.0 since the beginig there have only been 2 options 120hz and 60 hz so i downloaded cru and now the max is 134 i cannot put it a hertz higher for it to work if someone could please help me i would be very greatful.

You need to be more specific. 144 Hz at what resolution? What monitor? What laptop? Do you know what GPU the laptop has? Are you sure it's HDMI 2.0? Did you read about the pixel clock limits in the first post?

Sorry for late response I am using 100% HDMI 2.0 monitor-24" MSI Optix G24C4 GPU is Intel Core i5 11400H Tiger Lake
MSI Katana GF66 - laptop 144hz at 1920x1080 and I tried the pixel clock thing for nividia but it says file too large or something

also tried with other patop 144.01hz showed automatically worked like magic it has to be something with this laptop cable n monitor work