Clock Rate - Historical Milestones and Current Records

Historical Milestones and Current Records

The first commercial PC, the Altair 8800 (by MITS), used an Intel 8080 CPU with a clock rate of 2 MHz (2 million cycles/second). The original IBM PC (c. 1981) had a clock rate of 4.77 MHz (4,772,727 cycles/second). In 1992, both Hewlett-Packard and Digital Equipment Corporation broke the difficult 100 MHz limit with RISC techniques in the PA-7100 and AXP 21064 DEC Alpha respectively. In 1995, Intel's P5 Pentium chip ran at 100 MHz (100 million cycles/second). In March 6, 2000, AMD reached the 1GHz barrier a few months ahead of Intel. In 2002, an Intel Pentium 4 model was introduced as the first CPU with a clock rate of 3 GHz (three billion cycles/second corresponding to ~3.0×10−10seconds or 0.3 nanoseconds per cycle). Since then, the clock rate of production processors has increased much more slowly, with performance improvements coming from other design changes.

As of 2011, the Guinness Record for fastest CPU is by AMD with a Bulldozer based FX chip "overclocked" to 8.308 GHz; however, it has now been superseded by the next generation of AMD's Bulldozer based FX chips with a clock rate of 8.429 GHz. As of mid-2012, the highest clock rate on a production processor is the IBM z196, clocked at 5.2 GHz, which was released in June of 2010.