What is cpu: Definition and 118 Discussions

A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs).
The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers and other components.
Most modern CPUs are implemented on integrated circuit (IC) microprocessors, with one or more CPUs on a single IC chip. Microprocessor chips with multiple CPUs are multi-core processors. The individual physical CPUs, processor cores, can also be multithreaded to create additional virtual or logical CPUs.An IC that contains a CPU may also contain memory, peripheral interfaces, and other components of a computer; such integrated devices are variously called microcontrollers or systems on a chip (SoC).
Array processors or vector processors have multiple processors that operate in parallel, with no unit considered central. Virtual CPUs are an abstraction of dynamical aggregated computational resources.

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  1. J

    Understanding the ALU: Uncovering CPU Functionality

    Hi! I am new here and I have come to feed and develop my curiosity in mathematics and sciences. School is not enough I guess... The ALU is the part of the CPU in which every instruction is executed, right? But I don't understand, the OS itself is a software in machine language, it is...
  2. S

    C# Is it possible to create a C++/C# app for monitoring CPU temperature?

    Hi All, I have done a lot of searching and it seems like a lot of people ask this same question but no real answers. I'm wanting to create an app that reads the cpu temp constantly. I want to create this in a windows form gui, but since this information is so scarce i'll settle for a console...
  3. F

    CPU Deterioration: Do Computer Parts Decrease in Performance?

    Do computer parts like the CPU and GPU sort of decrease in performance over time? If so, by how much?
  4. J

    CPU has built-in circuitry to do simple arithmetic operations

    Hi I'm a layman so please keep your reply as simple as possible. Thanks. They say that a CPU has built-in circuitry to do simple arithmetic operations such as addition, subtraction, etc. and logical operation such as greater than, less than, etc. I don't understand how could some...
  5. C

    Performance of CPU: CPI, Interrupts & Shadow Registers

    A micro-instruction sequencing and execution machine has a clock cycle time of 10 ns and a base Cycle Per Instruction (CPI) of 5. The possibility of interrupts and (or) exceptions may happen in the middle of an instruction that must have copies of the values of the registers at the beginning of...
  6. N

    Writing About an Operation: 3-bus CPU

    Hey guys... here is the thing.. i kinda blur to talk about the operation.. i need help from u guys to give me ideas to write about the operation.. i attempted the question already.. but, i think it wasn't enough explanations. [PLAIN]http://img401.imageshack.us/img401/8831/74967107.jpg
  7. P

    How is the logical address space generated by the CPU?

    I do understand that logical address space/memory is generated by the CPU for the program and physical memory is the one on-to which the logical address space is mapped and which is on the physical memory. Plus, physical memory is not directly accessible to the user. Now, my question is (I...
  8. T

    Would a 10GHz CPU be as fast as a 2.5 GHz quad core CPU?

    Would a single 10GHz CPU be as fast as a quad-core CPU with each core running at 2.5 GHz? I would imagine that the caches on the Four processor cores would give it a performance advantage over the 10GHz single core. The way CPU manufacturers went after the days of highly-clocked processors...
  9. T

    What is the fastest GPU possible without bottlenecking this CPU?

    What is the fastest GPU setup you can have without encountering any major bottlenecks with an AMD Phenom II X4 965BE? Is it absolutely imperative to have a Core i7 clocked @ 4.0 GHz to properly run the latest graphics cards, especially in SLI/CrossfireX? My monitor only goes up to a 720p...
  10. T

    Is there any program I could download to display my CPU temperature?

    Right now, I can only view my CPU temperature in the BIOS menu. I can view my GPU temps in the ATI catalyst control center. I cannot view my CPU temperatures in windows vista home premium 64-bit. Is there any program I could download which would allow me to view my CPU temperatures in...
  11. J

    Can I Make a Quantum CPU? Exploring the Possibilities

    I just want to know. Is it possible to make a CPU in quantum? Or did I misunderstand the meaning of quantum computer?
  12. T

    Will this CPU be fully compatible with this motherboard?

    http://www.newegg.com/Product/Product.aspx?Item=N82E16813128358&cm_re=gigabyte_ep45ud3p-_-13-128-358-_-Product GIGABYTE GA-EP45-UD3P LGA 775 Intel P45 ATX Intel Motherboard Will my Intel Core 2 Quad Q9400 (2.66 GHz) be both physically, and electronically compatible with the motherboard in the...
  13. T

    CPU bottleneck by Radeon HD 5xxx series GPU's?

    I've read that the Radeon HD 5000 series graphics cards, especially the HD 5950, and 5970 dual-core ones, are being bottlenecked by even today's fastest available processors. Including the Core i7 975. A single Radeon HD 5970 (Two HD 5870 cores) has even more throughput than Two Radeon HD...
  14. T

    Calculators Are your OS/system/background tasks fully multi-threaded through a quad-core CPU?

    I was curious if your OS, and background/system tasks are fully multi-threaded throughout all the Four cores of a quad-core CPU. As well as all Eight threads, if that quad core supports hyper-threading. Most modern games, like Crysis, are only programmed to be threaded through Two processor...
  15. W

    After pressing the power button, when does the CPU, exactly, start working?

    and which part of it exactly receives the foremost electron?
  16. T

    Will my CPU bottleneck a GeForce GTX 285?

    Because my current graphics card runs burning-hot (past 100 *C) under load, I was hoping of getting a better, and hopefully cooler-running graphics card for Christmas. The overclocking features on my motherboard have been permanently disabled by the manufacturer (Gateway) making any kind of...
  17. R

    Is Pentium 4 CPU chip waterproof ?

    Dear Gurus, I have an old pentium chip covered with thermal paste that is kind of dried and difficult to remove. I intend to clean it with detergent and water. Would it still work after it is cleaned and dried? That is , is it waterproof? Thanks for taking time to read my question...
  18. S

    Creating a Cooled CPU System for Over-Clocking

    Hi all. I want to create a Cooler for my CPU to better over-clocking Because heat has a negative affect on cpu performance and because of my fancy. I speak about a closed tube that a liquid is injected in it. It should be has a little vacuum, because when the liquid is heated and therefore...
  19. M

    Do I Need More CPU Thermal Paste?

    I just installed a new power supply for my desktop last night. In the process I needed to remove the CPU heat sink. With no thermal paste on hand, I just reassembled the heat sink. The question is simply do I need to clean the CPU and reapply thermal paste since the heat sink was unseated?
  20. T

    Is it possible to upgrade the CPU with my motherboard?

    Click the link for specifications on my desktop computer. http://www.gateway.com/systems/product/529668208.php I was wondering if it is possible in terms of hardware compatibility to upgrade my CPU from a Intel Core 2 Quad Q9400 to an Intel Core 2 Extreme. I'm not sure if the...
  21. B

    How do I fix 100% CPU usage with explore.exe on my Vista computer?

    CPU 100% with explore.exe! After hunting down a solution for days now, I have finally narrowed the problem down using Process Explorer and Process Monitor, Anti-virus softwares and all that jazz. Now I have found a dead-end, and need help. System: Vista Home Premium x64 for Pavilion...
  22. D

    Making a CPU waterblock using a mill?

    So I really want to learn how to use a mill, and what better way than making something that's actually useful? Next semester we will be manufacturing an air compressor as a final design project. I'm hoping that I can figure out how to change it into a water pump (materials are NOT an issue...
  23. G

    Fortran Can software parallelization in Fortran reduce CPU usage and execution time?

    hello i have intel core 2 quad and my operating system is windows,every time i execute my fortran code it takes 8 hours to finish and just 25% of my cpu is used during the run(cpu usage=25%),it means just one core of my processor is used,so is there any way that i can use all the 4 cores of my...
  24. T

    What is the absolute fastest laptop CPU right now?

    I was just wondering what the absolute fastest laptop CPU that is currently available is, and could you link me to information about it?
  25. T

    In a CPU, what exactly is a cache ?

    In a CPU, what exactly is a "cache"? I was wondering what exactly a "Cache" is in a CPU. Why does having a larger cache improve performance? In the Phenom II and Core i7 processors, I noticed that they have a small amount of L2, and L3 cache, and 8 MB of L4 cache per core. What does this mean...
  26. T

    Will an Intel Core i7 920 be faster than this CPU?

    Will an entrance level Intel Core I7 920 be faster than a Core 2 Quad Q9400? Just asking...
  27. T

    CPU comparisons (I need your help)

    My old desktop PC which I built circa 2003, has officially stopped working. The parts in it are discontinued and I can't find them to buy anywhere. I am getting a new desktop as a christmas gift. I wanted you to tell me your professional opinion on which processor is better. I'm buying a...
  28. S

    Why Are CPU Prices Skyrocketing? Exploring the Factors Behind Rising CPU Costs

    The other day, watching to buy a new computer I saw CPU prices, and I asked myself why prices are so high. I mean, its just a tiny piece of semiconductor. Does the high price comes from the design of them, or it's that manufacturing them are expensive and machines to work at such small...
  29. T

    Will CPU stock clock speeds ever exceed 4.0 GHz?

    The fastest stock clock speed I have ever seen on a CPU the is currently available to the public is the Intel Core 2 Quad 4.0 GHz. (it may be overclocked) For the past few years, clocks on CPU's never seemed to get substantially higher. Is there some kind of thermal limit to how fast you can run...
  30. C

    What is causing my computer to slow down and how can I fix it?

    I'm running Windows XP on a dual-core notebook and I noticed that sometimes (like now ;)) the computer slows down dramatically as though under heavy load, but the task manager reports nothing: the system idle process claims 97% of the CPU and there's only ~500 MB of RAM in use (on a 2 GB...
  31. F

    The Physics Behind CPU Cooling with LN2 or Phase Change

    Hello everybody, my question is: do you get an increase in speed/power/performance when you "freeze" computer components such as the CPU with LN2 or phase change cooling, getting to under -100º,-150º. Because as long as I'm aware CPU´s are made out of semiconductors and as temp lowers the...
  32. C

    Exploring CPU Design: Major, Salary, & More

    I am interested in CPU design as well as computer hardware design. However, I could find very little information on CPU design. I was wondering what the best major would be, the salary, and any other information regarding this topic. Advice would be greatly appreciated. Thanks
  33. T

    Xeon CPU and NVidia Quadro screencard.

    Dear members, in a dell 650 workstation i have twin Xeon CPUs and NVidia Quadro screencard installed. Supposed to give good to excellent performance, however the rendering speed is extremely slow. The computer runs very slow compared to much less powerful configurations. There is no...
  34. T

    Number of Core’s vs CPU Hz Speed. What give fastest and most efficient rendering

    Dear members, I am going to build a new ws, and 1.st priority for this is rendering speed and 2nd stability. Prior to selection of hardware i sit with the following question. What will give max/ optimum speed and performance while rendering, as many number of cpu core’s as possible or...
  35. A

    Is My CPU Overloaded? Possible Causes and Solutions for Crackling Noise

    BURNING cpu?? since last 2-3 days, whenever my system gets overloaded(not just overloaded, even any process popping up in between some other one), i hear some crackling noise over my processor. is something wrong in there?? i know i don't have enough wattage SMPS, is it related something to...
  36. T

    Problem with oscilloscope hindering interrupt input on CPU

    I was trying to measure the delay time of an external interrupt by putting an oscilloscope probe on the input interrupt and a probe on an output pin. The interrupt is falling-edge triggered, so when i short the pin to ground, the interrupt is triggered. The pin has a 1M external pull up on the...
  37. O

    Is 91°C Too High for My CPU Temperature?

    My CPU temperature is high at 91°C or more after 5 minutes of working. The limits of threshold is 90°C and highest temperature is shown to be 100°C. I do not know what to do because I have to work. Please advice how to proceed! Thank you!
  38. Simfish

    How much CPU usage is required to slow system performance down?

    So I know that my CPU is now slowing down, even though Process Explorer reports system usage as varying between 30-70%, far short of 100% system usage. What is the most reliable way to measure system usage before the system starts to slow down?
  39. A

    Excessive CPU usage by explorer.exe

    I am using a 2.8Ghz Intel Dual core CPU and I've got Windows Vista Now...after a start my computer...a thread executes itself .The threads name is nxaEA8A.tmp... This uses upto 60% of the CPU acc to Process Explorer When i kill the thread my CPU usage comes back to normal. Any...
  40. O

    Can my CPU temperature be less than room temp?

    Is it possible that my cpu temp could be less than room temp with a standard fan and heatsink? I've been hearing that it's completely impossible to go below ambient room temperature because the fan is simply blowing air and not cooling anything. But what about when you turn the fan on in your...
  41. T

    CPU differences: quad core, dual core, etc. for CFD

    Hello all, I was wondering if anyone could help me figure out some differences between all the different types of processors out there for computers. I am a graduate student learning about CFD, and my advisor wanted me to check out some different processors because we would like to get new...
  42. P

    What is the maximum temperature for safe CPU overclocking?

    What is the highest temperature your CPU has reached? Mine is 150 degrees fahrenheit. This was on an Athlon XP.
  43. M

    CPU Cooling Project: Research, Testing & Analysis

    Hello, I am currently engaged in an High School chemistry project. I was wondering if you guys could help me out. The project itself is not required to be related to chemistry at all; it can be a physics/biology project as well. After some brainstorming, I have narrowed my topic down to...
  44. O

    What Motherboard Is Good For that CPU?

    Hi there, I need a good and handy way to findout, without too much pain, which motherboard is compatible with a certaini CPU. I usually check the motherboard manufacturer websites for this, but it takes me a lot of time. Do you know a website for that porpous? A place where you give them a...
  45. J

    Silicon photonics to take over CPU Industry?

    Hello all. I am finishing up my first year of a CE/EE major. I want to go into IC design; primarily for CPU's. I was wondering what you guys think that CPU's will use photonics extensively within the next 8-10 years. If the average CPU is photonic based within the next ten years, shouldn't...
  46. G

    High CPU Usage: My Computer Struggles To Run Multiple Programs

    my computer is wicked freaking slow and it crashes a lot too. I've run virus scans and defragmented and i did a disk clean up. lately I'm getting pretty familiar with task manager cause I'm always closing programs i don't need because other programs are slow. I'm always having really high cpu...
  47. N

    Can Pthreads Guarantee Exclusive CPU Assignment for Each Thread?

    Hi, First question is: I want to assign 8 threads to 8 processors (must one to one), when I initialize the thread, does it guarantee that each CPU has one thread? or there can be some case such that 4 threads on one process and other 4 thread on 4 processors and 3 processors have no threads...
  48. S

    Do I need Dual-core 64 bit CPU ?

    I am just a home user, my PC is intended for internet, music, movie, graphic and word processing, so, do i need a dual-core 64bit processor?
  49. C

    Design a CPU for Photocopier: 5 Inputs, 5 Outputs

    hello ladies and gentlemen; i've a more complex homework this time. i'm writing my homework down: "The design of central process unit of a photocopier is wanted." The inputs of cpu are; copy number in 3 bits, "start copying" input, the input of a sensor (the function of the sensor...
  50. H

    Unravelling the Mystery of an Optical CPU

    A few days ago a buddy of mine showed me a two year old article, telling that Israel have developed an optical CPU. I did check i further and it is true, but I can not understand how such a device can work.. Is there anyone who could explain it to me?
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