A higher-performance, more graphically capable revision of the PC-8001, the Mark II debuted in March 1983 for a price of 123,000 yen.

While its most obvious improvement was in its graphical capabilities, the Mark II also included an internal 5.25" floppy disk interface as well as two internal expansion slots, doing away with the need for an "expansion box" to permit upgrades.

The internal BASIC was changed as well, from the 24KB N-BASIC to a 32KB "N80-BASIC" that added new conditional statements as well as graphics commands.

While the price of the PC-8001mkII was comparable with other 8-bit computer offerings at the time, its graphics were notably worse than its competitors (most likely an attempt on NEC's part to avoid competing with their own, higher-powered PC-8800 series). This caused not much software to be produced for it, particularly games.

The Z80 quickly became popular in the personal computer market, with many early personal computers, such as the TRS-80 and Sinclair ZX80, using the Z80 as their central processing unit (CPU). It was also widely used in home computers, such as the MSX range, SORD, and the Amstrad CPC, as well as in many arcade games. Additionally, it was also used in other applications such as industrial control systems, and embedded systems. The Z80 was widely used until the mid-1980s, when it was gradually replaced by newer microprocessors such as the Intel 80286 and the Motorola 68000.

The Z80 microprocessor was developed by Zilog, a company founded by Federico Faggin in 1974. The Z80 was released in July 1976, as a successor to the Intel 8080. It was designed to be fully compatible with the 8080, but also included new features such as an improved instruction set, more powerful interrupts, and a more sophisticated memory management system.

Originally the Z80 was intended for use in embedded systems, just as the 8080 CPU. But the combination of compatibility, superior performance to other CPUs of the era, and the affordability led to a widespread use in arcade video game systems, and later in home computers such as the Osborne 1, TRS-80, ColecoVision, ZX Spectrum, MSX, Sega's Master System and many more. The Z-80 ran the original Pac-Man arcade cabinet. The Z-80 was used even in the Game Gear (1990s), and the TI-81 and succeeding graphic calculators.

The Z-80 remained in production until June of 2024, 48 years after its original release. Zilog replaced the processor with its successor the eZ80, an 8-bit microprocessor that features expanded memory addressing up to 16 megabytes, and running up to 50MHz, comparable to a Z80 clocked at 150MHz.