Vertical total calculator

Custom Resolution Utility (CRU) 1.5.2 has a new vertical total calculator that can be used to create lower refresh rates with a specific pixel clock. This makes it easier to implement Quick Frame Transport (QFT), which can help reduce crosstalk with backlight strobing at lower refresh rates.

Start with an existing high refresh rate detailed resolution:

Change the timing to "Vertical total calculator":

Enter a lower refresh rate.

The vertical total is automatically calculated based on the entered refresh rate and pixel clock.

In this mode, the frequency radio buttons determine the rounding method:

  • If refresh rate is selected, the pixel clock is rounded down to get closer to the entered refresh rate.
  • If pixel clock is selected, the pixel clock is left unchanged, but the actual refresh rate might be slightly higher than entered.

Custom Resolution Utility (CRU) 1.5.2

Changes in 1.5.2:

  • Support up to 7 extension blocks
  • NVIDIA can now read all extension blocks
  • Detailed resolutions:
    • Added 480p/480i/525p/525i to "Automatic CRT"
    • Fixed "Exact" and "Exact reduced" for interlaced resolutions
    • Added "Exact CRT" timing option
    • Added "Vertical total calculator" timing option
  • Audio formats: added "Auro-Cx" and "MPEG-D USAC" from CTA-861.6
  • Colorimetry: added "sRGB" and "Default RGB" from CTA-861.6

GUIDE: How to remove 4096x2160

Some 4K UHD TVs define 4096x2160 even though their native resolution is 3840x2160. This can cause scaling problems when games automatically choose the highest resolution or when using NVIDIA's Dynamic Super Resolution (DSR). This guide will show you how to disable 4096x2160 using Custom Resolution Utility (CRU).

4096x2160 can exist in these CTA-861 data blocks:

  • TV resolutions
  • HDMI support
  • 4:2:0 resolutions

Edit the CTA-861 extension block:

Edit the "TV resolutions" data block:

Delete all of the 4096x2160 resolutions:

Click the "OK" button.

Edit the "HDMI support" data block:

In the "HDMI resolutions" section, delete 4096x2160 @ 24 Hz if it exists:

Click the "OK" button.

Edit the "4:2:0 resolutions" data block if it exists:

Delete all of the 4096x2160 resolutions:

Click the "OK" button on all of the dialogs. Then run restart.exe or reboot.

After following this guide, 4096x2160 should no longer exist. To revert all changes, run reset-all.exe and reboot.

Custom Resolution Utility (CRU) 1.5.1

Changes in 1.5.1:

  • Audio formats: added new formats from CTA-861-G/H
  • Colorimetry: added ICtCp from CTA-861-H
  • DisplayID 2.0 detailed resolutions: fix "Reset" button resetting to 6 Hz when adding a new resolution
  • Tiled display topology: split vendor and product IDs to accommodate OUIs (2.0) and non-letter IDs (1.3)
  • List boxes now retain scroll position after editing

Custom Resolution Utility (CRU) 1.5

Changes in 1.5:

  • Added DisplayPort YCbCr color formats and maximum color depth (use the "Edit..." button at the top)
  • Added HDMI 2.1 features including maximum FRL rate, variable refresh rate, and display stream compression
  • New and improved timing options for detailed resolutions:
    • "LCD standard" has been split into "Automatic (PC)" and "Automatic (HDTV)" to better accommodate different display standards.
      The main difference is how they handle resolutions greater than 1920x1080 @ 60 Hz and 21:9 resolutions. "PC" favors CVT-RB, while "HDTV" favors CTA-861.
    • "LCD native" has been split into "Native (PC)" and "Native (HDTV)" for the same reason.
    • "LCD reduced" has been eliminated because it was too arbitrary and only worked for certain resolutions. Try "Exact reduced" for an alternative.
    • "CRT standard" is now "Automatic (CRT)" and includes 4:3/5:4 VESA DMT resolutions. Use "CVT standard" for the old behavior.
    • Added "Exact" and "Exact reduced" to calculate exact integer refresh rates.
    • Added common display standards: CVT, CVT-RB, CVT-RB2, and GTF (previously "Old standard")
  • Detailed resolutions can now calculate frequencies for all possible pixel clocks (up to 167772.16 MHz for DisplayID 1.3)
  • CEA-861 extension blocks are now called CTA-861 to reflect the standard's new name
  • Added support for DisplayID 2.0 extension blocks
  • Export now saves the original unmodified EDID if no changes were made

Fixing overscan issues

Overscan is a common issue with HDTVs, but there are some steps you can take to disable overscan:

  • Check the TV's settings and see if there is an option to disable overscan.
  • Use CRU to edit the affected detailed resolution and choose "CVT-RB standard" timing. This will use a different timing standard that some TVs will not overscan.
  • If you don't need HDMI audio, use CRU to delete the extension block, or edit the extension block and delete HDMI support. This will cause the GPU to send a DVI signal, which most TVs will not overscan. This will not work with 4K TVs.
  • Use the graphics driver's control panel to scale the image down. This will affect image quality.

List of EDID editors

Custom Resolution Utility (CRU) is an EDID editor that focuses on custom resolutions. Besides CRU, here are some other EDID editors:

  • Phoenix EDID Designer - Commonly referenced on forums but out of date. Does not support EDID 1.4 or extension blocks.
  • Deltacast E-EDID Editor - Similar to Phoenix but updated to support EDID 1.4 and CTA-861 extension blocks.
  • AW EDID Editor - Supports EDID 1.4 and CTA-861 extension blocks but not HDMI data blocks. Has a Mac version as well.
  • Advantiv EEditGold and EEditZ - The most complete EDID editors. Supports EDID 1.4 and CTA-861 extension blocks with many types of data blocks.

CRU can import and export files compatible with these editors.

Timing parameters explained

Active is the visible resolution.

Blanking is the period between each line (horizontal blanking) and each frame (vertical blanking). This was originally intended to give CRT monitors time to move the electron guns. LCD monitors don't need as much time, so the blanking can be reduced.

Blanking = front porch + sync width + back porch

Front porch, also known as sync offset, is basically padding before the sync pulse.

Sync width is the duration of the sync pulse. The sync pulse marks the start of the next line (horizontal sync) and the next frame (vertical sync).

Sync polarity is whether the sync pulse voltage goes up (+) or down (−). Most monitors can handle both.

Back porch is basically padding after the sync pulse, before the start of the active pixels.

Total is the total number of pixels including blanking.

Total = active + blanking


Refresh rate is the number of screen refreshes per second.

Horizontal scan rate is the total number of horizontal lines per second including blanking.

Horizontal scan rate = vertical total × refresh rate

Pixel clock is the total number of pixels per second including blanking.

Pixel clock = horizontal total × vertical total × refresh rate

See also: Common pixel clock limits

What timing parameters should I use?

Use whatever works. Standards exist to make sure certain values always work so devices can operate with each other, but if you're trying resolutions or refresh rates that the monitor doesn't officially support, there's no guarantee any particular timing parameters will work.