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.
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. 
VRR compatibility and implimentations
|Nouveau||Not Supported||Not Supported|
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
Gsync monitors should automatically be enabled. To enable Gsync compatible monitors do the following:
- In 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 VRR Range of a FreeSync 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 likeor .
You can edit this file withAUR
Process of overclocking on Linux: 
Section "Screen" Identifier "Screen0" Device "nvidia" # e.g. Radeon, nvidia Monitor "DP1" Option “CustomEDID” “MONITOR:/home/USER/Desktop/modified-edid.bin” EndSection
Tips and Tricks
Remove applications from Blacklist
Mesa has a list of blacklisted applications to avoid unexpected behavior, you can edit this blacklist here:
- Wayland is not supported.
- On Linux, the monitor must be plugged in via display port. Some monitors with the HDMI 2.1 specification can use FreeSync on Windows and this will likely be supported by Linux in the future. 
- Only one monitor may be used at a time with Gsync and possibly Freesync.
- Compositors will most likely need to be disabled before the OpenGl/Vulkan program is started.
- Mesa blacklists many applications including video players.
- Although tearing is much less noticeable at higher refresh rates, FreeSync monitors often have a limited range for their VRR of 90Hz, which can be much lower than their max refresh rate. See Change VRR Range of a FreeSync Monitor.