Vendor and game agnostic latency reduction middleware. An alternative to NVIDIA Reflex.
There is a phenomenon commonly known among gamers, where input lag would increase when the game FPS is left uncapped and the game reaches maximum GPU utilization. [video]
The reason this happens is that GPU work is dispatched asynchronously, and when the GPU reaches maximum utilization, it fails to catch up to the CPU and creates a queue of work, resulting in extra latency.
The traditional solution to this was to cap the framerate at the highest number the machine can sustain: it creates a CPU-bound scenario, and combined with variable refresh-rate support like FreeSync, it could consistently achieve the lowest possible input lag. The obvious drawback with this method is that the limit sacrifices the frame rate even when machine could run at a higher frame rate.
LatencyFleX is an easy-to-integrate solution that achieves the same minimal latency as capping the frame rate, while dynamically adapting to workload, unleashing the system's full rendering potential. It takes inspiration from researches in internet congestion control, where a similar problem called Bufferbloat has been studied.
- LatencyFleX current does not provide any benefits when VSync is enabled.
This is blocked on presentation timing support.
- LatencyFleX introduces jitter in frame time as a part of its algorithm, which results in microstutters.
Though, most games tend to have a larger frame time fluctuation already, so this is likely unperceivable.
- Minor stutters might happen during gaming session. The algorithm is still being tuned, but open an issue if the stutter is severe.
- GPU utilization will be lower when running with LatencyFleX. Overall LatencyFleX should be able to achieve ~95% utilization (assuming GPU bound). Open an issue if utilization is significantly low.
Building from source
The layer (
layer/) depends on CMake, Meson and the Vulkan SDK.
Build and install with:
cd layer meson build ninja -C build meson install -C build --skip-subprojects
The Wine extension (
layer/wine/) additionally depends on a Wine installation.
cd layer/wine export LIBRARY_PATH="$PWD/../build/" # Required if the layer has not been installed globally meson build ninja -C build
See install instructions for the locations to copy the files to.
LatencyFleX Vulkan layer (essential)
For Debian-like distros, copy the following files from release artifacts to your root filesystem.
For Arch-like distros, you need to copy
/usr/lib/x86_64-linux-gnu/liblatencyflex_layer.so -> /usr/lib/liblatencyflex_layer.so and additionally update the path specified in
LatencyFleX Wine extensions (required for Proton Reflex integration)
Copy the following files from release artifacts to your Wine installation location.
For Wine 7.x (including Proton-GE-Custom): change
/usr/lib/wine to wherever Wine/Proton is installed. For Proton and certain distros, you also need to change
lib64. Copy the following files.
For Wine <= 6.x and current Proton versions: copy the files as follows:
/usr/lib/wine/x86_64-unix/latencyflex_wine.dll.so -> lib64/wine/latencyflex_wine.dll.so /usr/lib/wine/x86_64-windows/latencyflex_wine.dll -> lib64/wine/fakedlls/latencyflex_wine.dll
DXVK-NVAPI with LatencyFleX integration (required for Proton Reflex integration)
Obtain binaries from GitHub Actions.
For Proton, copy
For other Wine installations, see DXVK-NVAPI documentation.
MangoHud with metric support (optional)
Obtain binaries from GitHub Actions and install it to your system.
Put the following line in
MangoHud.conf to have real-time latency metrics:
For now, LatencyFleX can be used through one of the following injection method. Game engine integration is planned.
Running games with LatencyFleX
Warning: Avoid using LatencyFleX with anti-cheat enabled games! It can almost certainly get you banned.
||Linux UE4 Hook|
Game supported but not in list? File a PR to update the table.
Proton NVAPI (for games that already have NVIDIA Reflex integration)
Install the Vulkan layer, wine extension and the modified branch of DXVK-NVAPI.
Put the following in
dxvk.conf (only for DX11 games):
dxgi.nvapiHack = False dxgi.customVendorId = 10de # If running on non-NVIDIA GPU
Launch with the following environment variables:
PROTON_ENABLE_NVAPI=1 DXVK_NVAPI_DRIVER_VERSION=49729 DXVK_NVAPI_ALLOW_OTHER_DRIVERS=1 LFX=1 %command%
Note: for now, the UE4 hook only supports Linux UE4 builds with PIE disabled.
Install the Vulkan layer.
The first step is to obtain an offset to
FEngineLoop::Tick. If the game ships with debug symbols, the offset can be obtained with the command:
readelf -Ws PortalWars/Binaries/Linux/PortalWars-Linux-Shipping.debug | c++filt | grep FEngineLoop::Tick
Find the line corresponding to the actual function (other entries are for types used in the function and unrelated):
268: 00000000026698e0 9876 FUNC LOCAL HIDDEN 15 FEngineLoop::Tick()
26698e0 is the offset we need. We will call it
Then, modify the launch command-line as follows.
LFX=1 LFX_UE4_HOOK=0x<OFFSET> %command%