NVIDIA Reflex is an SDK for game developers for measuring and reducing rendering latency. But now there is an alternative, open-source implementation of those APIs that can work across drivers/vendors while still helping to reduce rendering latency: meet LatencyFleX.
LatencyFleX is a vendor/game agnostic latency reduction middleware solution that can be used as a drop-in replacement to NVIDIA Reflex usage. LatencyFleX can work with Windows games running on Linux under Steam Play via Proton-NVAPI integration. There is also experimental support for directly hooking into Unreal Engine 4 and Unity games.
NVIDIA’s overview of their Reflex SDK.
This independently developed, open-source project has been tested with games like Ghostrunner, Splitgate, and Overwatch that support NVIDIA Reflex.
LatencyFleX
For those interested in learning more about this new open-source project there is the LatencyFleX GitHub. This blog post by Tatsuyuki Ishi covers the pursued approach for vendor-agnostic game rendering latency reduction while working with (theoretically) any game that supports NVIDIA Reflex. Interesting work!