486The fourth generation of the Intel x86 family of CPU chips. The term may refer to the chip or to a PC that used it. Introduced in 1989, it was the successor to the 386 and the first chip in the line to include a built-in math coprocessor. Providing acceptable performance for DOS, it was bare minimum for Windows. Later versions of the chip doubled and tripled internal speeds (see DX2 and DX4). See OverDrive CPU, PC and x86.
Type: 32-bit multitasking microprocessor
Transistors: 1,100,000 to 1,200,000 (1.0 micron)
Package: 168 or 169-pin PGA
Registers: 32 32-bit
Real Mode: Performs as a 16-bit 8086 CPU; addresses 1MB memory.
Protected Mode: Addresses 4GB physical and 64TB virtual memory; provides access to memory protection and 32-bit instructions.
Virtual 8086 Mode: Protected Mode subset that runs a Real Mode application in a virtual machine.