The speed of visible light is equal to the speed of gamma rays.
Both visible light and gamma rays travel through a vacuum with the same speed which is about 3.0 x 10⁸ meters per second. Both visible light and gamma rays are electromagnetic waves which travel through space with the speed of light which is 3.0 x 10⁸ m/s. The speed of light is the fastest speed possible, nothing travels faster than the speed of light .