386 is 1985, 10, 17, 80386DX officially released 27.5W transistors, which were originally 12.5MHz, and later upgraded to 20 MHz, 25 MHz, 33 MHz and a few 40MHz products.

486 is the 80486 introduced in 1989, which integrates the transistor of 120W. The manufacturing process of 1 micron is improved from 25MHz to 33MHz.40MHz.50MHz

586 came out in the mid-1990s, and Intel named it Pentium to show the difference. AMD and Cyrix also introduced K5 and 6x86 processors respectively.

Central processing unit (CPU) is a very large scale integrated circuit, which is the computing core and control unit of a computer. Its function is mainly to interpret computer instructions and process data in computer software.

Central processing unit mainly includes arithmetic logic unit (ALU) and cache, and data, control and status buses to realize the connection between them. Together with memory and input/output (I/O) devices, it is called the three core components of electronic computer.

Physical structure: CPU includes arithmetic logic unit, register unit and control unit.

Working process: CPU takes instructions from memory or cache, puts them into instruction register, and decodes them. It decomposes an instruction into a series of micro-operations, and then issues various control commands to execute the micro-operation series, thus completing the execution of an instruction. Instruction is the basic command of computer to specify operation type and operand. An instruction consists of one or more bytes, including an operation code field, one or more fields related to operand addresses, some status words representing the machine state and characteristic codes. Some instructions also directly contain the operands themselves.