The Acorn Archimedes is in fact a common term for a series of computers sold by Acorn Computers Limited, between 1987 and 1992, which were based on their 32 bit ARM RISC processor, which was significantly faster than the popular 68000 series of chips in use at the time.

The early computers (the A300 and A400 series) were sold under both the BBC Archimedes and the Acorn Archimedes brand, building on the company's earlier success with the BBC-Micro.

The A300 was the first Acorn Archimedes computer, which had an official upgrade to provide 2 expansion slots.  The A400 which followed, had 4 built-in expansion slots as well as a ST506 hard disk controller.  Both models featured the Arthur OS, although this could later be upgraded to the better RISC OS, BBC BASIC and an emulator to run earlier BBC-Micro software.  8 Channel sound and 256 onscreen colours helped to put this above its rivals, although it only ever attracted a niche market.

The A5000 was probably the pinnacle of this series, with a 25Mhz ARM3 RISC processor (compared to the earlier 8MHz) and also support for VGA resolutions of up to 800x600 pixels.

The series finished with the launch in September 1992 of the A3010, A3020 and A4000 computers, which were smaller computers using the ARM 250 RISC processor, aimed squarely at the home computer market.

These were succeeded in 1994 by the launch of RISC PCs which could run Linux.