Microprocessor Features

Microprocessor Year Used in: Features
8086 1978 PC/XT
  • 16-bit microprocessor 
  • 16-bit data bus 
  • 10 MHZ clock 
  • 1 MB address space
8088 1979 PC/XT
  • 8-bit data bus 
  • slower clock 
  • less expensive than 8086
80286/80288 1982 AT/PS2
  • 16-bit microprocessor/bus 
  • 12.5 MHz clock 
  • real address mode --- allows use of 8086 functions 
  • protected virtual mode --- supports multitasking, memory protection,  
  • 16 MB address space, 
  • virtual memory --- can use external memory as storage and execute programs up to 1 GB
80386         1985 PS2
  • 32-bit processor/bus 
  • 33 MHz clock speed 
  • 4 GB address space 
80386SX    
  • Same processor,  16-bit data bus
80486 1989 PS2
  • 32-bit processor with floating point unit built in
  • parallel decoding/execution of instructions
80486SX    
  • Floating point unit disabled
Pentium (80586) ~1993  
  • superscalar design - two instruction pipelines
  • branch prediction logic
  • 64-bit internal data path
  • separate caches for data, code
  • Dual integer processor -- 2 instructions per clock cycle