Sega’s Mega Drive manual describes Sonic as having “super speed” and says holding left or right makes him accelerate. It gives no real-world speed in meters per second, so Sega’s own instructions don’t assign him a numerical top speed.
Sega’s manual describes acceleration, not a speed figure
The manual explains the basic feel of Sonic’s movement: keep a direction held and he speeds up. Sega’s official history calls an unprecedented sense of speed the original game’s design concept, and dates its North American release to June 23, 1991. Sega’s Sonic history
The manual’s “super speed” is a description of the game’s feel, not a measurement. Its instructions explain how the player accelerates Sonic, but give no meters-per-second value. Read Sega’s Mega Drive manual
The Mega Drive HAA-2500 had separate processors and memory
Sega’s specification for the Mega Drive model HAA-2500 lists a 68000 main CPU at 7.67 MHz and a Z80A sub-CPU at 3.58 MHz. It also separates memory by function: 64 KB of RAM for the 68000, 8 KB for the Z80, and 64 KB of video RAM. Sega’s HAA-2500 specifications
Those figures describe the listed console model. They provide hardware context for the game, while the manual describes Sonic’s movement in player-facing terms.
Why estimates of Sonic’s speed differ
Third-party calculations put Sonic’s speed at different figures because they use different methods. A Sonic Retro forum participant estimated about 8.43 m/s by assuming Sonic moves at 6 pixels per frame on flat ground, using a scale of 42.65625 horizontal pixels per meter and a frame rate of approximately 59.92275 Hz. Other forum participants challenged assumptions behind the calculation. The Sonic Retro discussion
A separate estimate reported by TechTimes puts Sonic at a little over 10 m/s by dividing an estimated 259-meter level length by a 25-second completion. That result is an average across the run, not an instantaneous top speed. TechTimes’ account of the estimate
The two numbers aren’t interchangeable: one converts an assumed flat-ground pixel rate, while the other averages distance over a level completion. Neither is a Sega figure for Sonic’s instantaneous top speed.
Speed caps vary across classic Sonic games
A speed cap is a limit on how fast a character can move within a game. Carls493’s guide compares speed-cap behavior in Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic CD, and Sonic 3 & Knuckles. Its description characterizes the behavior as different between games and says Sonic 3 & Knuckles apparently has no cap.
