Custom Resolution Utility (CRU)

[ToastyX]

(08-31-2026 05:01 PM)true39 Wrote:  I have an RTX 4090; I was able to remove the resolution on my LG C5 using this same card, but it doesn't work with the G6. I’ve attached a file and would appreciate your help or an explanation of why this is happening. Thanks.

I already explained what's happening:

(08-31-2026 01:12 AM)ToastyX Wrote:  That's probably the DSC single-head limit issue mentioned in the first post. Also when that happens, DSR wouldn't be available anyway unless you disable using multiple heads or disable DSC in the TV, which would remove 165 Hz.

Here is the issue in the first post:

NVIDIA and DSC - ToastyX Wrote:NVIDIA's driver currently ignores EDID overrides if Display Stream Compression (DSC) is active and the maximum resolution @ refresh rate combination exceeds the GPU's single-head pixel clock limit:

GTX 1600-series: 1330 MHz
RTX 2000-series: 1330 MHz
RTX 3000-series: 1335 MHz
RTX 4000-series: 1350 MHz
RTX 5000-series: Not affected

Workarounds:

1. SRE can add custom GPU-scaled resolutions but not custom refresh rates: https://www.monitortests.com/forum/Threa...Editor-SRE
2. Use RegEdit to disable using multiple heads, but the pixel clock will be limited to the single-head limit:
   Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\#### (usually 0000)
   Value: "EnableTiledDisplay"=dword:00000000
   

3840x2160 @ 165 Hz is beyond the single-head limit for 4000-series GPUs. The registry workaround will work but it will disable 165 Hz. 144 Hz is still within the limit.

[true39]

(08-31-2026 06:53 PM)ToastyX Wrote:  

(08-31-2026 05:01 PM)true39 Wrote:  I have an RTX 4090; I was able to remove the resolution on my LG C5 using this same card, but it doesn't work with the G6. I’ve attached a file and would appreciate your help or an explanation of why this is happening. Thanks.

I already explained what's happening:

(08-31-2026 01:12 AM)ToastyX Wrote:  That's probably the DSC single-head limit issue mentioned in the first post. Also when that happens, DSR wouldn't be available anyway unless you disable using multiple heads or disable DSC in the TV, which would remove 165 Hz.

Here is the issue in the first post:

NVIDIA and DSC - ToastyX Wrote:NVIDIA's driver currently ignores EDID overrides if Display Stream Compression (DSC) is active and the maximum resolution @ refresh rate combination exceeds the GPU's single-head pixel clock limit:

GTX 1600-series: 1330 MHz
RTX 2000-series: 1330 MHz
RTX 3000-series: 1335 MHz
RTX 4000-series: 1350 MHz
RTX 5000-series: Not affected

Workarounds:

1. SRE can add custom GPU-scaled resolutions but not custom refresh rates: https://www.monitortests.com/forum/Threa...Editor-SRE
2. Use RegEdit to disable using multiple heads, but the pixel clock will be limited to the single-head limit:
   Key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\#### (usually 0000)
   Value: "EnableTiledDisplay"=dword:00000000
   

3840x2160 @ 165 Hz is beyond the single-head limit for 4000-series GPUs. The registry workaround will work but it will disable 165 Hz. 144 Hz is still within the limit.

Thanks a lot for the reply—it turns out it's all so complicated. It’s not exactly what you expect when you simply change your TV. =)

[newneonnew]

System specs:
GPU: RTX 5070
Monitor: KTC H27E6
Connection: Using DisplayPort 2.1 cable
CRU Version 1.5.3
Windows 11
Nvidia Studio Driver version 616.92

Monitor has a factory FreeSync range data block (48-255 Hz) in its CTA-861 extension block. Nvidia App shows G-SYNC: Not available for this display. Windows Settings > Advanced Display shows Variable Refresh Rate: Not Supported for this display, even on the correct DisplayPort connection at native 2560x1440 300Hz.

Already tried:

• enabled Adaptive Sync/FreeSync in monitor OSD
• connected via DisplayPort
• updated to latest Nvidia Studio driver
• edited existing FreeSync range block in CRU (tried 48-300, but OK was grayed out, so currently sitting at 48-255)
• ran restart64.exe
• full system reboot
• unplugged/replugged DP cable
  

None of these changed the 'Not Supported' status in Windows

[ToastyX]

(10-01-2026 09:19 PM)newneonnew Wrote:  System specs:
GPU: RTX 5070
Monitor: KTC H27E6
Connection: Using DisplayPort 2.1 cable
CRU Version 1.5.3
Windows 11
Nvidia Studio Driver version 616.92

Monitor has a factory FreeSync range data block (48-255 Hz) in its CTA-861 extension block. Nvidia App shows G-SYNC: Not available for this display. Windows Settings > Advanced Display shows Variable Refresh Rate: Not Supported for this display, even on the correct DisplayPort connection at native 2560x1440 300Hz.

Already tried:

• enabled Adaptive Sync/FreeSync in monitor OSD
• connected via DisplayPort
• updated to latest Nvidia Studio driver
• edited existing FreeSync range block in CRU (tried 48-300, but OK was grayed out, so currently sitting at 48-255)
• ran restart64.exe
• full system reboot
• unplugged/replugged DP cable
  

None of these changed the 'Not Supported' status in Windows

NVIDIA doesn't read the FreeSync data block, but it does support adaptive sync, which gets the refresh rate range from the range limits descriptor. It would be unusual for a DisplayPort monitor that supports FreeSync to not support adaptive sync. Is the range limits descriptor shown in the detailed resolution list in the main window?

[newneonnew]

(10-01-2026 10:51 PM)ToastyX Wrote:  

(10-01-2026 09:19 PM)newneonnew Wrote:  System specs:
GPU: RTX 5070
Monitor: KTC H27E6
Connection: Using DisplayPort 2.1 cable
CRU Version 1.5.3
Windows 11
Nvidia Studio Driver version 616.92

Monitor has a factory FreeSync range data block (48-255 Hz) in its CTA-861 extension block. Nvidia App shows G-SYNC: Not available for this display. Windows Settings > Advanced Display shows Variable Refresh Rate: Not Supported for this display, even on the correct DisplayPort connection at native 2560x1440 300Hz.

Already tried:

• enabled Adaptive Sync/FreeSync in monitor OSD
• connected via DisplayPort
• updated to latest Nvidia Studio driver
• edited existing FreeSync range block in CRU (tried 48-300, but OK was grayed out, so currently sitting at 48-255)
• ran restart64.exe
• full system reboot
• unplugged/replugged DP cable
  

None of these changed the 'Not Supported' status in Windows

NVIDIA doesn't read the FreeSync data block, but it does support adaptive sync, which gets the refresh rate range from the range limits descriptor. It would be unusual for a DisplayPort monitor that supports FreeSync to not support adaptive sync. Is the range limits descriptor shown in the detailed resolution list in the main window?

Yes, the range limits descriptor already exists with 48-300Hz. Saved via CRU, ran restart64.exe, full reboot — Windows Advanced Display still shows 'Variable Refresh Rate: Not Supported' and Nvidia App still shows G-SYNC as unavailable. Given the range limits are present and correctly formed, is there something else in the EDID that could be blocking Windows/Nvidia from recognizing adaptive sync support? Could the leftover FreeSync data block (48-255Hz) in the CTA extension be conflicting with this range limits descriptor rather than being redundant? I would send a screenshot of the CRU menu but I don't know how to attach it to this message.

[ToastyX]

(10-02-2026 05:58 PM)newneonnew Wrote:  Yes, the range limits descriptor already exists with 48-300Hz. Saved via CRU, ran restart64.exe, full reboot — Windows Advanced Display still shows 'Variable Refresh Rate: Not Supported' and Nvidia App still shows G-SYNC as unavailable. Given the range limits are present and correctly formed, is there something else in the EDID that could be blocking Windows/Nvidia from recognizing adaptive sync support? Could the leftover FreeSync data block (48-255Hz) in the CTA extension be conflicting with this range limits descriptor rather than being redundant? I would send a screenshot of the CRU menu but I don't know how to attach it to this message.

NVIDIA ignores the FreeSync data block so it won't conflict. I'm more interested in where it's saying "G-SYNC: Not available for this display." I'd run reset-all.exe and reboot first because it should work out of the box without changing anything in CRU. Then in the NVIDIA control panel, do you see Display > Set up G-SYNC? You have to enable G-SYNC, select the correct display if there is more than one, check "Enable settings for the selected display model" and apply the changes. You can attach an image and click add attachment, then insert into post.

[AssadFaszad]

(08-24-2026 10:41 PM)ToastyX Wrote:  

(08-22-2026 03:58 PM)AssadFaszad Wrote:  Hi,
I've got a laptop 1440p@165Hz GSync Compatible screen. I've managed to overclock it to 180Hz without frameskipping. Then I've adjusted V rate range to 180Hz. Windows 11 24H2 lists VRR as "Supported by driver" above 165Hz however it seems to be working fine. Curiously the original EDID has the range as 60-165Hz despite Windows and LFC kicking in at 70Hz. Changing the ID from CSO1509 to even a true GSync panel or one with a wider range removes GSync from NVCP. Are there any tricks or other improvements I could do? Here's the original EDID.

That's all there is to do. Your limitation will be the actual hardware and not anything in the EDID.

I've tried out CRU WIP and managed to finally modify the VRR range outside of the 2 predefined ranges. The predefined ranges are 70-165Hz and 25-60Hz. 70-165Hz blacks out below 60Hz when bypassed. Didn't yet break through 25Hz. What helped was either the G-SYNC or HDMI v2 Data Blocks.

Is it usual for a panel to have 2 ranges? Does it have an effect on overdrive or other things? The laptop specific issue of having "overdrive applied twice" is now yet again present.

With the modified range LFC doesn't kick in at all, or well, I can't see when it does if it happens below 60Hz. And the lower range seems to kick in LFC when below 26Hz.

Even if Windows control panel states that VRR is "Supported by driver", SpecialK recognizes it properly now and the panel uses the modified range.

What does it mean for Windows and software, when Active signal mode and Desktop mode differ?

[ToastyX]

(10-04-2026 10:07 PM)AssadFaszad Wrote:  I've tried out CRU WIP and managed to finally modify the VRR range outside of the 2 predefined ranges. The predefined ranges are 70-165Hz and 25-60Hz. 70-165Hz blacks out below 60Hz when bypassed. Didn't yet break through 25Hz. What helped was either the G-SYNC or HDMI v2 Data Blocks.

Is it usual for a panel to have 2 ranges? Does it have an effect on overdrive or other things? The laptop specific issue of having "overdrive applied twice" is now yet again present.

You mean two range limits descriptors? That's not common. There should only be one, and the driver would probably only listen to one of them. If HDMI VRR is defined in the HDMI v2 data block, that would take precedence on an HDMI connection, but that shouldn't have any effect on the laptop display. I'm not sure how NVIDIA would handle a G-SYNC block being present.

(10-04-2026 10:07 PM)AssadFaszad Wrote:  With the modified range LFC doesn't kick in at all, or well, I can't see when it does if it happens below 60Hz. And the lower range seems to kick in LFC when below 26Hz.

Even if Windows control panel states that VRR is "Supported by driver", SpecialK recognizes it properly now and the panel uses the modified range.

What does it mean for Windows and software, when Active signal mode and Desktop mode differ?

When the resolutions are different, it means the desktop resolution is being scaled to the active resolution. The refresh rates aren't supposed to be different. I don't even understand how that happens.

[MUC]

(10-04-2026 10:07 PM)AssadFaszad Wrote:  Are there any tricks or other improvements I could do? Here's the original EDID.

The panel is a device from China Star Optoelectronics Technology (CSOT), connected via the DisplayPort protocol, likely a 40-pin eDP connection with 4 lanes (HBR3).

Adding HDMI VRR to the EDID should have no effect whatsoever. For DisplayPort "G-Sync Compatible" (=VESA AdaptiveSync) operation, the Nvidia driver only evaluates the range limits from the base block. According to your original EDID, the video timing for 165 Hz complies with the VESA CVT-RB standard.

Therefore, it should be sufficient to adjust the range limits and add the 180 Hz mode (using CVT-RB timing) to the extension block.

Please try the attached EDID.