Sinclair ZX81 emulators

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Sinclair ZX81
Developer Sinclair Research
Type Computers
Generation Z80-based home computers
Release date 1981
Discontinued 1984
Predecessor Sinclair ZX80
Successor ZX Spectrum

The ZX81 was a Z80-based home computer produced by Sinclair Research and manufactured in Scotland by Timex Corporation.

It was the successor to Sinclair's ZX80 and the predecessor of the ZX Spectrum and was hugely successful, and more than 1.5 million units were sold before it was discontinued. The ZX81 was designed to be small, simple, and above all cheap, using as few components as possible to keep the cost down.

Video output was to a television set rather than a dedicated monitor. Programs and data were loaded and saved onto audio tape cassettes. It had only four silicon chips on board and a mere 1 KB of memory. The machine had no power switch or any moving parts and used a pressure-sensitive membrane keyboard for manual input.

Its distinctive design brought its designer, Rick Dickinson, a Design Council award. The ZX81 could be bought by mail order in kit form or pre-assembled. It was the first cheap mass-market home computer that could be bought from high street stores, led by W.H. Smith and soon many other retailers.

The ZX81 marked the first time that computing in Britain became an activity for the general public, rather than the preserve of businesspeople and electronics hobbyists. The ZX81's commercial success made Sinclair Research one of Britain's leading computer manufacturers and earned a fortune and an eventual knighthood for the company's founder, Sir Clive Sinclair.


Name Operating System(s) Latest Version ZX80 ZX81 Libretro Core Active Relative Speed[1] Recommended
EightyOne Windows 1.12 114.3%
ZEsarUX Multi-platform 7.1 110.9%
CLK macOS and UNIXalikes 2020-05-10 100.0%
SZ81 UNIX, Windows, Amiga 2.1.7 ? 100.0%
MAME Multi-platform 0.221 ? ? Not tested
  1. As calculated by Carlo Delhez's clkfreq, originally distributed with his XTender emulator. The ZX81 has relatively complicated timing mechanics, depending on signalling of WAIT during NMI; relative speed is a measurement of how closely an emulator matches a real machine in terms of clock cycles spent processing within a frame. 100.0% denotes the same execution speed as a real machine.