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Add info for frame delay
There is video latency caused by the GL drivers in Windows/Linux. It is a total black box and they do all sorts of crazy buffering schemes under the hood for all sorts of purposes - better scores with benchmarking tests, better "game" results - but it is actually counter productive when your aim is low-latency audio/video synchronization for emulators - you don't want all this stuff going on in the background. This applies to both GLX X11 drivers and Windows GL/D3D drivers - both are full of bad hacks and codepaths that cater to benchmarking applications and games.
Hard syncing option GPU sync options in some emulators emulator frontends can reduce or remove thislatency from buffering at the possible expense of performance.
This can be avoided by using KMS and DRM/EGL, specifically on Linux; using these, 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. AMD, Nvidia) do not find KMS a priority. Intel graphics chips, however, should be fine regardless, but it is still advisable to update drivers.
*Linux OS in KMS mode
To disable Windows Aero under Windows Vista/7, select the Basic or Classic theme under Control Center > Personalization, or disable desktop composition under .exe properties > Compatibility. Desktop composition will also be disabled by playing under non-windowed fullscreen. In Windows 8, desktop composition cannot be disabled manually.
Some emulator frontends such as RetroArch or GroovyMAME have the option to delay processing of emulation for a few milleseconds until right before a vsync occurs, which causes inputs to be polled immediately before your display refreshes instead at the beginning of the 16.7ms (for 60 fps) vsync period. The amount of time you can use frame delay without dropping frames is dependent on the performance of the emulator on your machine.
==References==
