Variable refresh rate
Variable refresh rate (VRR), also referred to as adaptive sync, allows the monitor to adjust its refresh rate to the output signal. This allows for games to eliminate screen tearing with less of the usual downsides of Vsync (such as stuttering). For a comprehensive look at VRR see PC Gaming Wiki.
Contents
Overview
There are multiple implementations of VRR:
- FreeSync is AMD's implementation of VESA's VRR standard, and the phrases are often used interchangeably. FreeSync branded monitors should be compatible with all VESA compatible drivers.
- Gsync is NVIDIA's proprietary hardware and software implementation of VRR.
- Intel plans on implementing VESA's standard in their upcoming 10th Gen. [1]
VRR compatibility and implimentations
Driver | VESA | Gsync |
---|---|---|
AMDGPU | FreeSync | No |
Intel | Planned | No |
Nouveau | Not Supported | Not Supported |
NVIDIA | Gsync Compatible | Gsync |
Configuration
Enable on AMDGPU
Using a Xorg conf file
Add the line to your .conf file.
Option "VariableRefresh" "true"
For more information on Xorg configuration see the AMDGPU page.
Verify vrr_capable is set to 1 using xrandr:
$ xrandr --props
vrr_capable: 1 range: (0, 1)
Enable on NVIDIA
Using a Xorg conf file
Via nvidia-settings
- In nvidia-settings go to the "X Server Display Configuration" page, then under the Advanced button is the option to "Allow G-SYNC on monitor not validated as G-SYNC Compatible". Then click apply.
- Now, under OpenGL settings, check "Allow Gsync/Gsync Compatible."
Change Freesync Range of Monitor
Freesync monitors usually have a limited range for VRR that are much lower than their max refresh rate. It should be possible to overclock the monitor to change the Freesync range.
Editing the EDID File
External Display Identification Data (EDID) stores driver information about your monitor. By default, this file is sent by your monitor and read on connect. You will need to extract this file using something like read-edid or nvidia-settings.
You can edit this file with wxedidAUR
You may follow one of the guides of people changing the freesync range on Windows: [2][3]
Process of overclocking on Linux: [4]
Make a Xorg .conf file for your monitor and add a path to the custom EDID file you have edited. See xrandr to find find out the other information about your monitor.
/etc/X11/xorg.conf.d/10-monitor.conf
Section "Screen" Identifier "Screen0" Device "nvidia" # e.g. Radeon, nvidia Monitor "DP1" Option “CustomEDID” “MONITOR:/home/USER/Desktop/modified-edid.bin” EndSection
xrandr –query
command.Tips and Tricks
Remove applications from Blacklist
Mesa has a list of blacklisted applications to avoid unexpected behavior, you can edit this blacklist here:
/usr/share/drirc.d/00-mesa-defaults.conf
Limitations
- For Gsync, the monitor must be plugged in via display port. For Freesync, some monitors with the HDMI 2.1 specification is supported otherwise display port will be needed.
- Only one monitor may be used at a time with Gsync and possibly Freesync.
- Some compositors may need to be disabled before the OpenGl/Vulkan program is started.
- Mesa blacklists many applications including video players.
- Although tearing is much less of an issue at higher refresh rates, most Freesync monitors only have a range up to 90Hz see Change Freesync range of Monitor