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| '''Central processing unit power dissipation''' or '''CPU power dissipation''' is the process in which [[central processing unit]]s (CPUs) consume [[electrical energy]], and dissipate this energy both by the action of the switching devices contained in the CPU (such as [[transistor]]s or [[vacuum tube]]s) and by the energy lost in the form of [[heat]] due to the [[Electrical impedance|impedance]] of the [[electronic circuit]]s. | | We know the famous BMI or Body Mass Index Calculation so popular to assess whether you're general, overweight or obese? So, what do you absolutely learn about it? Do you think it's important?<br><br>Doctors plus dietitians utilize body mass index (BMI) and measurement of the waist to assess a person's risk of developing certain illnesses, by way of example, diabetes plus heart condition. If your BMI is better than 25, you're overweight. BMI equal to or better than 30 indicates obesity.<br><br>BMI Plus Strategies to Improve NutritionSome of the issues are caused by children spending less time playing physically active games and more time inside front of the TV, the computer, or with a game movie system. Additionally, families are busier on the whole today so more fast food is bought plus nutritious home-cooked food aren't cooked because frequently.<br><br>First, you need to determine an BMI for the child. What is a BMI? BMI stands for body mass index that is a amount that takes into account a child's height-to-weight ratio. There is a rather complex formula for calculating BMI, however this is done promptly and easily at a variety of online sites that provide a [http://safedietplansforwomen.com/bmi-calculator bmi calculator]. You simply plug in a child's weight and height plus the program might calculate your child's BMI. Choosing a bmi calculator is as simple because doing a Google look for which phrase.<br><br>If you are planning on going to the gym, taking a friend a lengthy may give you the self-confidence to keep going plus the two of you are able to cheer every additional on in the fight to burn which fat! Exercising daily can be stressful on the body, though. Try doing a regular routine every additional day, then between do a 30 walk on the treadmill or ride found on the bicycle!<br><br>You are able to moreover calculate a waist-hip ratio (WHR) by dividing your waist measurement by cool measuring. Studies show which the WHR of women of any build strongly affects the perception of bodily attractiveness across all creeds plus cultures. Studies show which the most appealing women (according to guys!) are those who have 0.7 WHR (waist circumference is 70% of the hip circumference). Do you know that super stars Marilyn Monroe, Sophia Loren and the Venus de Milo had WHRs around 0.7?<br><br>Cancer, inside countless cases, is triggered by unabsorbed fatty cells in the body. These fats produce hormones inside body. These hormones, if yielded in large quantities, may trigger the growth of tumors plus eventually cause cancer. Heart attack is another quite common problem which fat individuals face. The fats deposited found on the walls of arteries block the usual flow of the blood and make the heart muscles weak. Besides these, deficiency of sleep is also 1 of the effects of weight. |
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| == CPU power management ==
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| {{See also|Variable TDP}}
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| Designing CPUs that perform tasks [[Energy conversion efficiency|efficiently]] without [[thermal shock|overheating]] is a major consideration of nearly all CPU manufacturers to date. Some implementations of CPUs use very little power; for example, the CPUs in [[mobile phone]]s often use just a few hundred [[watt|milliwatts]] of electricity. Some [[microcontrollers]], used in [[embedded systems]] may use a few milliwatts. In comparison, CPUs in general purpose [[personal computer]]s, such as [[desktop computer|desktops]] and [[laptop]]s, dissipate significantly more power because of their higher complexity and speed. These microelectronic CPUs may consume power in the order of a few watts to hundreds of watts. Historically, early CPUs implemented with [[vacuum tube]]s consumed power on the order of many [[kilowatt]]s.
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| CPUs for desktop computers typically use a significant portion of the power consumed by the [[computer]]. Other major uses include fast [[video card]]s, which contain [[graphics processing unit]]s, and the [[Power supply unit (computer)|power supply]]. In laptops, the [[LCD]]'s backlight also uses a significant portion of overall power. While [[power management|energy-saving features]] have been instituted in personal computers for when they are idle, the overall consumption of today's high-performance CPUs is considerable. This is in strong contrast with the much lower energy consumption of CPUs designed for low-power devices. One such CPU, the [[Intel XScale]], can run at 600 [[Megahertz|MHz]] with only half a watt of power, whereas [[x86]] PC processors from Intel in the same performance bracket consume roughly eighty times as much energy.{{Citation needed|date=December 2009}} <!-- I'm only about 98% sure of this -->
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| There are some engineering reasons for this pattern.
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| * For a given device, operating at a higher [[clock rate]] always requires more power. Reducing the clock rate of the microprocessor through [[power management]] when possible reduces energy consumption.
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| * New features generally require more [[transistor]]s, each of which uses power. Turning unused areas off saves energy, such as through [[clock gating]].
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| * As a processor model's design matures, smaller transistors, lower-voltage structures, and design experience may reduce energy consumption.
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| Processor manufacturers usually release two power consumption numbers for a CPU:
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| * ''typical thermal power'', which is measured under normal load. (for instance, AMD's [[Average CPU power]])
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| * ''maximum thermal power'', which is measured under a worst-case load.
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| For example, the Pentium 4 2.8 GHz has 68.4 W typical thermal power and 85 W maximum thermal power. When the CPU is idle, it will draw far less than the typical thermal power. [[Datasheet]]s normally contain the [[thermal design power]] (TDP), which is the maximum amount of [[heat]] generated by the CPU, which the [[computer cooling|cooling system]] in a computer is required to [[dissipation|dissipate]]. Both Intel and [[Advanced Micro Devices]] (AMD) have defined TDP as the maximum heat generation for thermally significant periods, while running worst-case non-synthetic workloads; thus, TDP is not reflecting the actual maximum power of the processor. This ensures the computer will be able to handle essentially all applications without exceeding its thermal envelope, or requiring a cooling system for the maximum theoretical power (which would cost more but in favor of extra headroom for processing power).<ref>{{cite web
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| | url = http://www.silentpcreview.com/article169-page3.html
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| | title = Athlon 64 for Quiet Power | page = 3
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| | date = 2004-06-15 | accessdate = 2013-12-21
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| | author = Mike Chin | publisher = silentpcreview.com
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| | quote = Thermal Design Power (TDP) should be used for processor thermal solution design targets. The TDP is not the maximum power that the processor can dissipate.
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| }}</ref><ref>{{cite web
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| | url = http://arstechnica.com/gadgets/2013/01/the-technical-details-behind-intels-7-watt-ivy-bridge-cpus/
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| | title = The technical details behind Intel's 7 Watt Ivy Bridge CPUs
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| | date = 2013-01-14 | accessdate = 2013-01-14
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| | publisher = arstechnica.com
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| | quote = In Intel's case, a specified chip's TDP has less to do with the amount of power a chip needs to use (or can use) and more to do with the amount of power the computer's fan and heatsink need to be able to dissipate while the chip is under sustained load. Actual power usage can be higher or (much) lower than TDP, but the figure is intended to give guidance to engineers designing cooling solutions for their products.
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| }}</ref>
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| In many applications, the CPU and other components are idle much of the time, so idle power contributes significantly to overall system power usage. When the CPU uses power management features to reduce energy use, other components, such as the motherboard and chipset, take up a larger proportion of the computer's energy. In applications where the computer is often heavily loaded, such as scientific computing, [[performance per watt]] (how much computing the CPU does per unit of energy) becomes more significant.
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| ==Sources of power consumption==
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| There are several factors contributing to the CPU power consumption; they include dynamic power consumption, short-circuit power consumption, and power loss due to [[transistor leakage current]]s:
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| <math>P_{cpu} = P_{dyn} + P_{sc} + P_{leak}</math>
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| The dynamic power consumption originates from logic-gate activities in the CPU. When logic gates toggle, energy is flowing as capacities inside the logic gates are charged and discharged. The dynamic power consumed by a CPU is approximately proportional to the CPU frequency, and to the square of the CPU voltage:<ref>{{cite web
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| | url = ftp://download.intel.com/design/network/papers/30117401.pdf
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| | title = Enhanced Intel SpeedStep Technology for the Intel Pentium M Processor (White Paper)
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| | month = March | year = 2004 | accessdate = 2013-12-21
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| | publisher = [[Intel Corporation]] | format = PDF
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| }}</ref>
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| :<math>P = C V^2 f</math>
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| where {{mvar|C}} is capacitance, {{mvar|f}} is frequency, and {{mvar|V}} is voltage.
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| When logic gates toggle, some transistors inside may change states. As this takes a finite amount of time, it may happen that for a very brief amount of time some transistors are conducting simultaneously. A direct path between the source and ground then results in some short-circuit power loss. The magnitude of this power is dependent on the logic gate, and is rather complex to model on a macro level.
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| Power consumption due to leakage power emanates at a micro-level in transistors. Small amounts of currents are always flowing between the differently doped parts of the transistor. The magnitude of these currents depend on the state of the transistor, its dimensions, physical properties and sometimes temperature. The total amount of leakage currents tends to inflate for increasing temperature and decreasing transistor sizes.
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| Both dynamic and short-circuit power consumption are dependent on the clock frequency, while the leakage current is dependent on the CPU supply voltage. It has been shown that the energy consumption of a program shows convex energy behavior, meaning that there exists an optimal CPU frequency at which energy consumption is minimal.<ref>{{cite paper | author = K. De Vogeleer et al.| title = The Energy/Frequency Convexity Rule: Modeling and Experimental Validation on Mobile Devices| version = 1.0| publisher = Springer| date = 9 September 2013 | url = http://arxiv.org/abs/1401.4655 | format = PDF| accessdate = 2014-1-21}}</ref>
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| ==Implications of increased clock frequencies==
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| Processor manufacturers consistently delivered increases in [[clock rate]]s and instruction-level parallelism, so that single-threaded code executed faster on newer processors with no modification.<ref>See Herb Sutter, [http://www.gotw.ca/publications/concurrency-ddj.htm The Free Lunch Is Over: A Fundamental Turn Toward Concurrency in Software], Dr. Dobb's Journal, 30(3), March 2005</ref> Now, to manage CPU power dissipation, processor makers favor [[multi-core]] chip designs, and software has to be written in a [[multi-threaded]] or multi-process manner to take full advantage of the hardware. Many multi-threaded development paradigms introduce overhead, and will not see a linear increase in speed vs number of processors. This is particularly true while accessing shared or dependent resources, due to [[Lock (computer science)|lock]] contention. This effect becomes more noticeable as the number of processors increases. Recently, IBM has been exploring ways to distribute computing power more efficiently by mimicking the distributional properties of the human brain.<ref>{{cite web|last=Johnson|url=http://www.eetimes.com/electronics-news/4218883/IBM-demos-cognitive-computer-chips|title=IBM demos cognitive computer chips|accessdate=10/1/11}}</ref>
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| ==See also==
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| {{Div col||23em}}
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| * [[power dissipation]]
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| * [[List of CPU power dissipation]]
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| * [[Power management]]
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| * [[Advanced Configuration and Power Interface]] (ACPI)
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| * [[Low-power electronics]]
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| * [[Dynamic frequency scaling|Frequency scaling]]
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| * [[Dynamic voltage scaling|Voltage scaling]]
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| * [[Overvolting]]
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| * [[Undervolting]]
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| * [[Overclocking]]
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| * [[Underclocking]]
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| * [[Performance per watt]]
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| * [[IT energy management]]
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| * [[Green computing]]
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| * [[Moore's law]]
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| {{Div col end}}
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| == Notes ==
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| {{Reflist|30em}}
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| == References ==
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| {{refbegin|30em}}
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| # {{cite paper | author=Weik, Martin H. | title=A Survey of Domestic Electronic Digital Computing Systems | publisher=United States Department of Commerce Office of Technical Services | url=http://www.computerhistory.org/collections/DocumentArchive/Documents/Books/Ballistic%20Research%20Lab%20surveys%20of%20computers/BRL%20Weik%20Report%201955/BRL.html | year=1955}}
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| # http://developer.intel.com/design/itanium2/documentation.htm#datasheets
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| # http://www.intel.com/pressroom/kits/quickreffam.htm
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| # http://www.intel.com/design/mobile/datashts/24297301.pdf
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| # http://www.intel.com/design/intarch/prodbref/27331106.pdf
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| # http://www.via.com.tw/en/products/processors/c7-d/
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| # http://mbsg.intel.com/mbsg/glossary.aspx
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| # http://download.intel.com/design/Xeon/datashts/25213506.pdf
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| # http://www.intel.com/Assets/en_US/PDF/datasheet/313079.pdf, page 12
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| # http://support.amd.com/us/Processor_TechDocs/43374.pdf, pages 10 and 80.
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| {{refend}}
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| == External links ==
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| * [http://www.techarp.com/showarticle.aspx?artno=337 CPU Reference for all vendors. Process node, die size, speed, power, instruction set, etc.]
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| * [http://users.erols.com/chare/elec.htm Processor Electrical Specifications]
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| * [http://www.sizinglounge.com SizingLounge] – Online calculation tool for server energy costs.
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| * [http://processorfinder.intel.com/ For specification on Intel processors.]
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| [[Category:Central processing unit]]
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| [[Category:Electric power]]
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| [[de:CPU-Leistungsaufnahme]]
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| [[fi:Suorittimen tehonkulutus]]
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We know the famous BMI or Body Mass Index Calculation so popular to assess whether you're general, overweight or obese? So, what do you absolutely learn about it? Do you think it's important?
Doctors plus dietitians utilize body mass index (BMI) and measurement of the waist to assess a person's risk of developing certain illnesses, by way of example, diabetes plus heart condition. If your BMI is better than 25, you're overweight. BMI equal to or better than 30 indicates obesity.
BMI Plus Strategies to Improve NutritionSome of the issues are caused by children spending less time playing physically active games and more time inside front of the TV, the computer, or with a game movie system. Additionally, families are busier on the whole today so more fast food is bought plus nutritious home-cooked food aren't cooked because frequently.
First, you need to determine an BMI for the child. What is a BMI? BMI stands for body mass index that is a amount that takes into account a child's height-to-weight ratio. There is a rather complex formula for calculating BMI, however this is done promptly and easily at a variety of online sites that provide a bmi calculator. You simply plug in a child's weight and height plus the program might calculate your child's BMI. Choosing a bmi calculator is as simple because doing a Google look for which phrase.
If you are planning on going to the gym, taking a friend a lengthy may give you the self-confidence to keep going plus the two of you are able to cheer every additional on in the fight to burn which fat! Exercising daily can be stressful on the body, though. Try doing a regular routine every additional day, then between do a 30 walk on the treadmill or ride found on the bicycle!
You are able to moreover calculate a waist-hip ratio (WHR) by dividing your waist measurement by cool measuring. Studies show which the WHR of women of any build strongly affects the perception of bodily attractiveness across all creeds plus cultures. Studies show which the most appealing women (according to guys!) are those who have 0.7 WHR (waist circumference is 70% of the hip circumference). Do you know that super stars Marilyn Monroe, Sophia Loren and the Venus de Milo had WHRs around 0.7?
Cancer, inside countless cases, is triggered by unabsorbed fatty cells in the body. These fats produce hormones inside body. These hormones, if yielded in large quantities, may trigger the growth of tumors plus eventually cause cancer. Heart attack is another quite common problem which fat individuals face. The fats deposited found on the walls of arteries block the usual flow of the blood and make the heart muscles weak. Besides these, deficiency of sleep is also 1 of the effects of weight.