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→Ways to reduce input lag
As a side note, VSYNC ON in the NVIDIA Control Panel will only work for Fullscreen applications. In addition, MS Hybrid-based laptops do not support VSYNC ON. If you are gaming in windowed mode or on one of these laptops, and want to utilize G-SYNC + VSYNC + Reflex mode, use in-game VSYNC.<ref>[https://www.nvidia.com/en-us/geforce/guides/gfecnt/202010/system-latency-optimization-guide/ Nvidia: System latency optimization guide]</ref>
*Some graphics drivers enforce excessive frame buffering, which may be eliminated with GPU commands. [[RetroArch]]'s [[Vsync#Hard_GPU_Sync|Synchronization Fences/Hard Sync ]] for OpenGL does this. If using Vulkan, be sure to set the [https://arm-software.github.io/vulkan_best_practice_for_mobile_developers/samples/performance/swapchain_images/swapchain_images_tutorial.html max swapchain images] parameter to 2, though weaker GPUs, especially Intel iGPUs, can struggle with this, particularly if using shaders or increasing rendering resolution.
*A relatively new lag-mitigating technique known as [https://github.com/higan-emu/emulation-articles/tree/master/input/run-ahead Run-Ahead] has recently been implemented in several emulators and frontends, which leverages spare performance overhead to run one or more instances of the emulator ahead of the regular instance, then uses save state rollback to lay that instance over what you see, effectively cutting a whole frame or more of input lag. Most games, even on real hardware on a CRT, have at least one hard-coded frame between executing an action on the controller and said action being reflected on screen, so setting Run-Ahead to 1 frame cuts out that superfluous frame and thus is usually considered safe, but setting it to 2 or more can result in dropped frames and perceived video stutter (though some games can benefit from 2 or more frames, particularly a lot of 5th-gen games). This is also quite processor-heavy, as every extra Run-Ahead frame requires a whole extra instance of the emulator, easily doubling or tripling CPU load, and some emulators are currently not able to use Run-Ahead at all. That said, combined with all the other lag reduction techniques on a sufficiently powerful system, Run-Ahead in theory can actually result in less input lag than even real hardware.
**Another option for lag-mitigating technique known as Preemptive Frames. See [https://www.youtube.com/watch?v=NDYqRoyOKI4 this video] for information.
