Emulation Options
General Options
General Options
Set any speed value below to 0 to make Mesen-S run as fast as possible.
Emulation Speed: This configures the regular speed to use when emulating. This should normally be set to 100%.
Fast Forward Speed: This is the alternate speed that is used when the Fast Forward button is held down.
Rewind Speed: This configures the speed at which to rewind the gameplay when the Rewind button is held down.
Region: When set to Auto, the emulator will try to detect the game’s region (NTSC or PAL) - however, this is not always possible. When there is nothing to suggest a game is for the PAL region (Australia & Europe), the NTSC region (North America & Japan) will be used by default.
Run Ahead: Run ahead allows the reduction of input lag by the number of frames specified. CPU requirements increase proportionally with the number of run ahead frames specified.
- Run ahead is currently not compatible with movies or netplay - the movies and netplay menus will be disabled if runahead is turned on.
- Note for speedrunners: Using features such as run ahead to reduce lag typically counts as cheating for the purposes of speed running.
BS-X
BS-X Options
This section configures the date and time that BS-X/Satellaview games use. It can either be set to the current date and time, or to a specific date and time which is used each time a BS-X title is launched.
Advanced Options
Advanced Options
When developing software for the SNES, enabling these options can help you catch bugs. Setting the power on state for RAM to random values is also recommended.
Default power on state for RAM: On a console, the RAM’s state at power on is undetermined and relatively random. This option lets you select Mesen-S’ behavior when initializing RAM - set all bits to 0, set all bits to 1, or randomize the value of each bit.
Randomize power-on state: When enabled, various chips (PPU, etc.) often have a random state at power-on and need to be fully initialized before being used. This option causes their power on state to be random, forcing the program to initialize them to run properly.
Use strict board mappings: When enabled, this option turns on stricter board mappings for some cartridges. Currently, this only affects CX4 games.
Overclocking
Overclocking can cause issues in some games. The safest way to overclock is to increase the Additional scanlines before NMI option and leave the other options to their default values.
Overclocking Options
Additional scanlines before NMI: Increases the number of scanlines in the PPU, before the NMI signal is triggered at the end of the visible frame. This effectively gives more time for games to perform calculations, which can reduce slowdowns in games. This is the preferred option for overclocking.
Additional scanlines after NMI: Increases the number of scanlines in the PPU, after the NMI signal is triggered at the end of the visible frame. This effectively gives more time for games to perform calculations, which can reduce slowdowns in games. This option is less compatible and should only be used if the before NMI variation does not work as expected.
Super FX Clock Speed: Increases the clock speed used for the Super FX chip, which can reduce lag in Super FX games. This method of overclocking is more efficient for Super FX titles.