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===[[Wikipedia:Compositing_window_manager|Compositor]]===
If you're using Windows Vista/7 and playing in windowed mode, having [[Wikipedia:Desktop_Window_Manager|DWM]] enabled will add a noticeable amount of input lag because it forces vertical synchronization at the OS-level. The same thing applies to other OSes if their compositor uses V-Sync. [[Wikipedia:Windows_Aero|Windows Aero]] and [[Wikipedia:Desktop_Window_Manager|DWM]] can be disabled in both Vista and 7, thus disabling compositing and lowering input lag when playing in windowed mode, but this can no longer be done from Windows 8 onward due to [[Wikipedia:Windows_Display_Driver_Model#WDDM_1.2|WDDM 1.2+]]. That said, exclusive fullscreen should automatically disable compositing on all Windows OSes, making it the preferred way to emulate in most cases.
===GPU driver===
There is video latency caused by the GL drivers in Windows/Linux. Both the GLX X11 and Windows GL/D3D drivers are full of hacks, code paths, and buffer schemes that cater to benchmarking applications and games. This is counterproductive when the aim is low-latency audio and video synchronization for emulators. You don't want all this stuff going on in the background. This can be avoided by using [[Wikipedia:Mode_setting|KMS]] and [[Wikipedia:Direct_Rendering_Manager|DRM]]/[[Wikipedia:EGL_(API)|EGL]], specifically on Linux. By using these modes, the user is in control of front and back buffers and don't have to rely on APIs, so that they can find where and when a frame was dropped and how to act accordingly with that in mind. It is advisable to get the latest driver to improve performance, as notable graphics chip manufacturers (e.g. Nvidia) do not find KMS a priority.<ref>[https://developer.nvidia.com/blog/understanding-and-measuring-pc-latency/ nvidia: Understanding and Measuring PC Latency]</ref> Intel and most AMD graphics chips, however, should be fine regardless, but it is still advisable to update drivers.
→Causes
If you're in the market for a monitor or TV; check [[Input_lag#External_Links|these websites]] for input lag and display lag performance of various display products. Some of the modern displays only have negligible amount of input lag and display lag and even some of them are near identical performance compared to Analog CRTs.
===Input===
See [[#Ways_to_reduce_input_lag|ways to reduce input lag section]] for reducing input delay.
====[[Wikipedia:Compositing_window_manager|Compositor]]====
If you're using Windows Vista/7 and playing in windowed mode, having [[Wikipedia:Desktop_Window_Manager|DWM]] enabled will add a noticeable amount of input lag because it forces vertical synchronization at the OS-level. The same thing applies to other OSes if their compositor uses V-Sync. [[Wikipedia:Windows_Aero|Windows Aero]] and [[Wikipedia:Desktop_Window_Manager|DWM]] can be disabled in both Vista and 7, thus disabling compositing and lowering input lag when playing in windowed mode, but this can no longer be done from Windows 8 onward due to [[Wikipedia:Windows_Display_Driver_Model#WDDM_1.2|WDDM 1.2+]]. That said, exclusive fullscreen should automatically disable compositing on all Windows OSes, making it the preferred way to emulate in most cases.
====GPU driver====
There is video latency caused by the GL drivers in Windows/Linux. Both the GLX X11 and Windows GL/D3D drivers are full of hacks, code paths, and buffer schemes that cater to benchmarking applications and games. This is counterproductive when the aim is low-latency audio and video synchronization for emulators. You don't want all this stuff going on in the background. This can be avoided by using [[Wikipedia:Mode_setting|KMS]] and [[Wikipedia:Direct_Rendering_Manager|DRM]]/[[Wikipedia:EGL_(API)|EGL]], specifically on Linux. By using these modes, the user is in control of front and back buffers and don't have to rely on APIs, so that they can find where and when a frame was dropped and how to act accordingly with that in mind. It is advisable to get the latest driver to improve performance, as notable graphics chip manufacturers (e.g. Nvidia) do not find KMS a priority.<ref>[https://developer.nvidia.com/blog/understanding-and-measuring-pc-latency/ nvidia: Understanding and Measuring PC Latency]</ref> Intel and most AMD graphics chips, however, should be fine regardless, but it is still advisable to update drivers.
==Ways to reduce input lag==
