The 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
). See OverDrive CPU
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.