Editing Acorn Archimedes A4000 (section)

== Processor ==

The A4000 uses the '''ARM250''' at 12 MHz, the single-chip device that integrates an ARM2-class core, the MEMC1a memory controller, the VIDC1a video and sound controller, and the IOC input/output controller.<ref name="wp">[https://en.wikipedia.org/wiki/Acorn_Archimedes "Acorn Archimedes"], Wikipedia.</ref> (Some period Acorn material lists the integrated I/O part as "IOMD"; that is a later Risc PC chip, and the ARM250 integrates the IOC.)<ref name="wp" /><ref name="chris" /> Two A4000s measured for Chris's Acorns returned about 7.19 and 7.61 MIPS on the ARMSi benchmark, and roughly 5,400–5,600 Dhrystones per second, which is in line with the 12 MHz ARM250 in the A3020.<ref name="chris" />

A Chips & Technologies 82C711 peripheral controller provides the IDE, floppy, serial and parallel interfaces in a single support chip.<ref name="82c711">[https://arcwiki.org.uk/index.php/82C711 "82C711"], Arc Wiki.</ref>