The Sirius 1 became the most popular 16-bit business computer in Europe, especially in Britain and Germany, while IBM delayed the release of the PC there. Its success led to the Apricot PC or ACT Apricot in September 1983, based on an Intel 8086 microprocessor running at 4.77 MHz. It ran MS-DOS or CP/M-86 but was not compatible at a hardware level with the IBM PC. It had two floppy disks, and was one of the first systems to use 3.5" disks, rather than the 5.25" disks which were the norm at the time.