6 Manufacturer : Sega Year of Release : 1991 Units sold : 30 million Best-selling game : Sewer Shark CPU : 16-bit Motorola 68000 @ 12.5 MHz + Megadrive CPUs RAM : 512kB / VRAM : 256kB / sound RAM : 16kB Video : Custom ASIC Resolution : 320×224 pixels, 64 colors (512 colors palette) Sound : Ricoh RF5C164 + Megadrive Sound chips Media : 500MB CD-ROM discs