It is also surpassed by the slightly slower AMD FX-8370 overclocked to 8.72 GHz which tops of the HWBOT frequency rankings. This is surpassed by the CPU-Z overclocking record for the highest CPU clock rate at 8.79433 GHz with an AMD FX-8350 Piledriver-based chip bathed in LN2, achieved in November 2012. Set in 2011, the Guinness World Record for the highest CPU clock rate is 8.42938 GHz with an overclocked AMD FX-8150 Bulldozer-based chip in an LHe/ LN2 cryobath, 5 GHz on air. Since then, the clock rate of production processors has increased much more slowly, with performance improvements coming from other design changes. In 2002, an Intel Pentium 4 model was introduced as the first CPU with a clock rate of 3 GHz (three billion cycles per second corresponding to ~ 0.33 nanoseconds per cycle).

On March 6, 2000, AMD demonstrated passing the 1 GHz milestone a few days ahead of Intel shipping 1 GHz in systems. In 1995, Intel's P5 Pentium chip ran at 100 MHz (100 million cycles per 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. The first commercial PC, the Altair 8800 (by MITS), used an Intel 8080 CPU with a clock rate of 2 MHz (2 million cycles per second). As each instruction took 20 cycles, it had an instruction rate of 5 kHz. The first electronic general purpose computer, the ENIAC, used a 100 kHz clock in its cycling unit. The first fully mechanical analog computer, the Z1 operated clock frequency at 1 Hz (cycle per second) clock frequency and the first electromechanical general purpose computer, the Z3, operated at a frequency of about 5–10 Hz. Historical milestones and current records There is also a lower limit of the clock rate, unless a fully static core is used. Transistors may be damaged by excessive heat. When executing complicated instructions that cause many transitions, the higher the clock rate the more heat produced. In the process of transitioning, some energy is wasted as heat (mostly inside the driving transistors). If the next clock pulse comes before that, the results will be incorrect. That is, every signal line must finish transitioning from 0 to 1, or from 1 to 0. However, the amount of overclocking is limited by the time for the CPU to settle after each pulse, and by the extra heat created.Īfter each clock pulse, the signal lines inside the CPU need time to settle to their new state. Conversely, some people try to increase performance of a CPU by replacing the oscillator crystal with a higher frequency crystal (' overclocking'). With any particular CPU, replacing the crystal with another crystal that oscillates at half the frequency (' underclocking') will generally make the CPU run at half the performance and reduce waste heat produced by the CPU. An A/D Converter has a 'clock' pin driven by a similar system to set the sampling rate. The clock distribution network inside the CPU carries that clock signal to all the parts that need it. Electronic circuitry translates that into a square wave at the same frequency for digital electronics applications (or, in using a CPU multiplier, some fixed multiple of the crystal reference frequency). Typically a crystal oscillator produces a fixed sine wave-the frequency reference signal. The clock rate of a CPU is normally determined by the frequency of an oscillator crystal.

Processors successfully tested for compliance with a given set of standards may be labeled with a higher clock rate, e.g., 3.50 GHz, while those that fail the standards of the higher clock rate yet pass the standards of a lesser clock rate may be labeled with the lesser clock rate, e.g., 3.3 GHz, and sold at a lower price. Chip manufacturers publish a 'maximum clock rate' specification, and they test chips before selling them to make sure they meet that specification, even when executing the most complicated instructions with the data patterns that take the longest to settle (testing at the temperature and voltage that runs the lowest performance). For a given CPU, the clock rates are determined at the end of the manufacturing process through actual testing of each processor. Manufacturers of modern processors typically charge premium prices for processors that operate at higher clock rates, a practice called binning.

Cpu speed test