The X Board is an arcade system board released by Sega in 1987 as a successor to Sega OutRun hardware. It debuted with After Burner and Thunder Blade.

The X Board specification is an expansion of the OutRun hardware, with more memory, and a more powerful GPU chipset, allowing for twice as many sprites/textures on screen at once, twice as many tile layers, a faster fillrate, more colors, and sprite/background rotation effects. The contents have also been condensed onto a single board, making it slightly easier to manufacture.

The X Board was the third in the Super Scaler series of arcade hardware, and would be succeeded by the Y Board and System 32, before the Model 1 made polygonal 3D arcade games more viable and financially affordable.

Hardware

As the third in Sega's Super Scaler series of arcade hardware (after the Sega Hang-On hardware and Sega OutRun hardware), it was noteworthy for its sprite/texture manipulation capabilities, which allowed it to create high quality three-dimensional visuals, such as the scaling and rotating environments in 1987's After Burner, and the ray casting like environments in 1988's Last Survivor and 1989's Line of Fire. This trend would continue with the Y Board and the System 32, before the Model 1 made true polygonal 3D arcade games more financially affordable.

The X Board hardware was originally developed for After Burner, which began development in December 1986 and released in 1987. The first challenge when creating the hardware was sprite/texture rotation, researching how to rotate the surfaces of the sprites, which was a major milestone. Another major milestone was making the smoke trails from missiles look more realistic.