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Clock Rates and Processor Performance
Clock Rates and Processor Performance
Published: 2014/10/22
Channel: 0612 TV w/ NERDfirst
Computer Performance: Relative Performance, CPU Time, Clock Cycle, Clock Rate
Computer Performance: Relative Performance, CPU Time, Clock Cycle, Clock Rate
Published: 2013/12/17
Channel: Q Liu
What is Clock Rate ? | CPU Speed Unit Explained In Hindi
What is Clock Rate ? | CPU Speed Unit Explained In Hindi
Published: 2016/11/07
Channel: Technical Sagar
CPU Clock Speeds - Do they Matter?
CPU Clock Speeds - Do they Matter?
Published: 2016/06/20
Channel: HowToCompute
Clock Rate vs Bandwidth - Configuring clock rate and bandwidth
Clock Rate vs Bandwidth - Configuring clock rate and bandwidth
Published: 2015/02/28
Channel: Tariq Abosallout
What is Clock Speed?
What is Clock Speed?
Published: 2014/06/30
Channel: NaxorTech
Clock rate
Clock rate
Published: 2016/02/12
Channel: Derpy Networking
Clock Speed Explained | GHz MHz etc. | What
Clock Speed Explained | GHz MHz etc. | What's the Deal?
Published: 2016/12/26
Channel: Technical Guruji
CPU Clock Speeds: Guide to the A+ Certification Exam (04:04)
CPU Clock Speeds: Guide to the A+ Certification Exam (04:04)
Published: 2015/11/24
Channel: Mr. Ford's Class
CPU Cores and Clock Speed - A Car Analogy
CPU Cores and Clock Speed - A Car Analogy
Published: 2017/05/31
Channel: Puget Systems
CCNA - Configuring The Clock Rate on Cisco Router.avi
CCNA - Configuring The Clock Rate on Cisco Router.avi
Published: 2010/12/11
Channel: Professor K
What is Pixel Clock Rate?  |  HowToAV
What is Pixel Clock Rate? | HowToAV
Published: 2016/04/27
Channel: HowToAV.tv
Instructions per cycle - Gary explains
Instructions per cycle - Gary explains
Published: 2016/08/01
Channel: Android Authority
Video Card Shopping Tips: Why Memory and Clock Speeds Don
Video Card Shopping Tips: Why Memory and Clock Speeds Don't Matter NCIX Tech Tips
Published: 2011/03/31
Channel: NCIX Tech Tips
All About Clock Rate - Todo Acerca del Clock Rate
All About Clock Rate - Todo Acerca del Clock Rate
Published: 2017/03/13
Channel: Christian Augusto Romero Goyzueta
Tutorial 2 (Part 1: CPU time calculation Demonstration)
Tutorial 2 (Part 1: CPU time calculation Demonstration)
Published: 2016/03/17
Channel: Ahmed Mosharafa
what does the CPU do ; how is the CPU affected by clock speed, cache memory and number of cores
what does the CPU do ; how is the CPU affected by clock speed, cache memory and number of cores
Published: 2015/08/23
Channel: Lord Logic's Computer Science channel
Cisco CCNA Training - Configuring a Serial Interface Connection Between Two Routers
Cisco CCNA Training - Configuring a Serial Interface Connection Between Two Routers
Published: 2016/05/01
Channel: John Yonan
Clockspeed
Clockspeed
Published: 2008/03/10
Channel: Isaac Cheang
Buckethead - clock rate- mix
Buckethead - clock rate- mix
Published: 2017/03/09
Channel: Bucket Sound
[Hindi/urdu]  processor Clock Speed? clock rate? what is Gzh in Snapdragon 820 chipset 2.5ghz
[Hindi/urdu] processor Clock Speed? clock rate? what is Gzh in Snapdragon 820 chipset 2.5ghz
Published: 2016/09/24
Channel: sambodhi
Understanding the CPU for beginners
Understanding the CPU for beginners
Published: 2012/12/30
Channel: TRUSTECH
Explaining CPU Architecture: Machine Cycle, Clock Rate & Cores - Ep. 1A
Explaining CPU Architecture: Machine Cycle, Clock Rate & Cores - Ep. 1A
Published: 2015/01/26
Channel: Sebastian Soeiro
*Hax 3DS HANS Clock Rate Comparison [804 Mhz/268 Mhz]
*Hax 3DS HANS Clock Rate Comparison [804 Mhz/268 Mhz]
Published: 2015/11/02
Channel: TCPixel
Initial rates and the iodine clock
Initial rates and the iodine clock
Published: 2015/05/03
Channel: Allery Chemistry
How we can configure Clock rate on a Cisco router in Hindi
How we can configure Clock rate on a Cisco router in Hindi
Published: 2014/06/14
Channel: Dilber Khan Networker
Dual Core @ 4 GHz vs Quad-Core @ 2 GHz: Which one performs better?
Dual Core @ 4 GHz vs Quad-Core @ 2 GHz: Which one performs better?
Published: 2016/10/02
Channel: OzTalksHW
STM32F4Discovery Tutorial 4 - Clock Frequency
STM32F4Discovery Tutorial 4 - Clock Frequency
Published: 2015/08/06
Channel: LogicVoltage
Digital Electronics: Maximum clock frequency in sequential logic (D FF example)
Digital Electronics: Maximum clock frequency in sequential logic (D FF example)
Published: 2014/06/07
Channel: sacademy
How to setup a clock rate on a DCE router ?
How to setup a clock rate on a DCE router ?
Published: 2016/12/29
Channel: Things of Computer Made Easy
HDL Coder Clock Rate Pipelining, Part 1: Introduction - MATLAB and Simulink video
HDL Coder Clock Rate Pipelining, Part 1: Introduction - MATLAB and Simulink video
Published: 2016/06/20
Channel: MATLAB
How to overclock your graphics card - check FPS, temp, clock speed
How to overclock your graphics card - check FPS, temp, clock speed
Published: 2016/08/29
Channel: SergeantPope - Komada Computer Repair
Cycles, Instructions and Clock Rate - Problem 1.5
Cycles, Instructions and Clock Rate - Problem 1.5
Published: 2016/12/05
Channel: Nicco Ciancarelli
HOW TO INCREASE CLOCK SPEED OF CPU IN YOUR ANDROID SMARTPHONE
HOW TO INCREASE CLOCK SPEED OF CPU IN YOUR ANDROID SMARTPHONE
Published: 2016/04/08
Channel: electro shubham
CLOCK RATE
CLOCK RATE
Published: 2012/09/28
Channel: sin steven
O’clock rate sa vidéo
O’clock rate sa vidéo
Published: 2016/11/23
Channel: O'clock
Resident  - Clock rate (Original mix)
Resident - Clock rate (Original mix)
Published: 2016/10/29
Channel: Resident
O.C.D. Clock Speed
O.C.D. Clock Speed
Published: 2012/05/02
Channel: WearetheOCDband
clock rate
clock rate
Published: 2010/07/22
Channel: carlin25103
router rip and clock rate By Cheaputheara
router rip and clock rate By Cheaputheara
Published: 2014/04/06
Channel: putheara Chea
Gaming PC More Cores or Higher Clock Speed (PM Response)
Gaming PC More Cores or Higher Clock Speed (PM Response)
Published: 2014/12/18
Channel: Adam Lubin
CC Clock Speed Adjustment
CC Clock Speed Adjustment
Published: 2014/09/28
Channel: Colonels Clocks
configure clock rate on router
configure clock rate on router
Published: 2017/01/14
Channel: My I.T
Setting The Clock Rate.avi
Setting The Clock Rate.avi
Published: 2011/10/14
Channel: snapieee
Tutorial 1 - Convert Period to Frequency
Tutorial 1 - Convert Period to Frequency
Published: 2012/10/14
Channel: C Orr
What Is Clock Speed And Bus Speed - How clock speed speeds up your computer ✔
What Is Clock Speed And Bus Speed - How clock speed speeds up your computer ✔
Published: 2017/02/06
Channel: Tech Geeks
HDL Coder Clock Rate Pipelining, Part 2: Optimization - MATLAB and Simulink Video
HDL Coder Clock Rate Pipelining, Part 2: Optimization - MATLAB and Simulink Video
Published: 2016/06/21
Channel: MATLAB
Materi 27   Frekuensi clock rate mikroprosesor
Materi 27 Frekuensi clock rate mikroprosesor
Published: 2017/04/06
Channel: Computer Hardware Technology
How Does CPU Speed Affect Gaming 3GHz Vs 4.5GHz | intel i7 5960X | GTX 1080 FE
How Does CPU Speed Affect Gaming 3GHz Vs 4.5GHz | intel i7 5960X | GTX 1080 FE
Published: 2016/07/16
Channel: Bang4BuckPC Gamer
Find Out Motherboard Serial & CPU Brand/Clock Speed Using Command Prompt Tutorial
Find Out Motherboard Serial & CPU Brand/Clock Speed Using Command Prompt Tutorial
Published: 2016/10/20
Channel: ComputerSluggish Tutorials
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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The clock rate typically refers to the frequency at which a chip like a central processing unit (CPU), one core of a multi-core processor, is running and is used as an indicator of the processor's speed. It is measured in clock cycles per second or its equivalent, the SI unit hertz (Hz), the clock rate of the first generation of computers was measured in hertz or kilohertz (kHz), but in the 21st century the speed of modern CPUs is commonly advertised in gigahertz (GHz). This metric is most useful when comparing processors within the same family, holding constant other features that may affect performance. Video card and CPU manufacturers commonly select their highest performing units from a manufacturing batch and set their maximum clock rate higher, fetching a higher price.

Determining factors[edit]

Binning[edit]

Manufacturers of modern processors typically charge premium prices for processors that operate at higher clock rates, a practice called binning. For a given CPU, the clock rates are determined at the end of the manufacturing process through actual testing of each processor. 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). 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.[1]

Engineering[edit]

The clock rate of a CPU is normally determined by the frequency of an oscillator crystal. Typically a crystal oscillator produces a fixed sine wave—the frequency reference signal. 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). The clock distribution network inside the CPU carries that clock signal to all the parts that need it. An A/D Converter has a "clock" pin driven by a similar system to set the sampling rate. With any particular CPU, replacing the crystal with another crystal that oscillates half the frequency ("underclocking") will generally make the CPU run at half the performance and reduce waste heat produced by the CPU. Conversely, some people try to increase performance of a CPU by replacing the oscillator crystal with a higher frequency crystal ("overclocking").[2] However, the amount of overclocking is limited by the time for the CPU to settle after each pulse, and by the extra heat created.

After each clock pulse, the signal lines inside the CPU need time to settle to their new state. That is, every signal line must finish transitioning from 0 to 1, or from 1 to 0. If the next clock pulse comes before that, the results will be incorrect. In the process of transitioning, some energy is wasted as heat (mostly inside the driving transistors). When executing complicated instructions that cause many transitions, the higher the clock rate the more heat produced. Transistors may be damaged by excessive heat.

Historical milestones and current records[edit]

The first electromechanical general purpose computer, the Z3 operated at a frequency of about 5–10 Hz. The first electronic general purpose computer, the ENIAC, used a 100 kHz clock in its cycling unit. As each instruction took 20 cycles, it had an instruction rate of 5 kHz.

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). The original IBM PC (c. 1981) had a clock rate of 4.77 MHz (4,772,727 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. In 1995, Intel's P5 Pentium chip ran at 100 MHz (100 million cycles per second). On March 6, 2000, AMD reached the 1 GHz milestone 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 per second corresponding to ~3.3×10−10seconds or 0.33 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 World Record for the highest CPU clock rate is an overclocked, 8.805 GHz AMD Bulldozer-based FX-8150 chip. It surpassed the previous record, a 8.670 GHz AMD FX "Piledriver" chip.[3]

As of mid-2013, the highest clock rate on a production processor is the IBM zEC12, clocked at 5.5 GHz, which was released in August 2012.

Research[edit]

Engineers continue to find new ways to design CPUs that settle a little more quickly or use slightly less energy per transition, pushing back those limits, producing new CPUs that can run at slightly higher clock rates. The ultimate limits to energy per transition are explored in reversible computing.

The first fully reversible CPU, the Pendulum, was implemented using standard CMOS transistors in the late 1990s at MIT.[4][5][6][7]

Engineers also continue to find new ways to design CPUs so that they complete more instructions per clock cycle, thus achieving a lower CPI (cycles or clock cycles per instruction) count, although they may run at the same or a lower clock rate as older CPUs. This is achieved through architectural techniques such as instruction pipelining and out-of-order execution which attempts to exploit instruction level parallelism in the code.

Comparing[edit]

The clock rate of a CPU is most useful for providing comparisons between CPUs in the same family. The clock rate is only one of several factors that can influence performance when comparing processors in different families. For example, an IBM PC with an Intel 80486 CPU running at 50 MHz will be about twice as fast (internally only) as one with the same CPU and memory running at 25 MHz, while the same will not be true for MIPS R4000 running at the same clock rate as the two are different processors that implement different architectures and microarchitectures. Further, a "cumulative clock rate" measure is sometimes assumed by taking the total cores and multiplying by the total clock rate(e.g. dual core 2.8 ghz being considered processor cumulative 5.6 ghz). There are many other factors to consider when comparing the performance of CPUs, like the width of the CPU's data bus, the latency of the memory, and the cache architecture.

The clock rate alone is generally considered to be an inaccurate measure of performance when comparing different CPUs families. Software benchmarks are more useful. Clock rates can sometimes be misleading since the amount of work different CPUs can do in one cycle varies. For example, superscalar processors can execute more than one instruction per cycle (on average), yet it is not uncommon for them to do "less" in a clock cycle. In addition, subscalar CPUs or use of parallelism can also affect the performance of the computer regardless of clock rate.

See also[edit]

References[edit]

  1. ^ [1] [2]
  2. ^ "Overclocking" early processors was as simple – and as limited – as changing the discrete clock crystal ... The advent of adjustable clock generators has allowed "overclocking" to be done without changing parts such as the clock crystal."-- Overclocking Guide Part 1: Risks, Choices and Benefits : Who Overclocks? by Thomas Soderstrom
  3. ^ Chiappetta, Marco (23 September 2011). "AMD Breaks 8 GHz Overclock with Upcoming FX Processor, Sets World Record". HotHardware. Retrieved 2012-04-28. 
  4. ^ Michael Frank. "RevComp - The Reversible and Quantum Computing Research Group".
  5. ^ Michael Swaine. "Backward to the Future". Dr. Dobb's Journal. 2004.
  6. ^ Michael P. Frank. "Reversible Computing: A Requirement for Extreme Supercomputing".
  7. ^ Matthew Arthur Morrison. "Theory, Synthesis, and Application of Adiabatic and Reversible Logic Circuits For Security Applications". 2014.

This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.

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