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. U

    Comp Sci X86 NASM reading from the terminal and writing back to the terminal

    cpu 8086 segment code ..start mov ax,data mov ds,ax mov ax,stack mov ss,ax mov sp,dno mov es, ax start_2 mov ah, 0x0a mov dx, buffer int 21h cmp al, 0 je print_lines inc word [count] mov si, buffer mov di, line mov cx, 100...
  2. Arman777

    Ipad Air 5th Gen M1 Hardware properties compared to Intel i5-7200U CPU

    Hey all, I want to buy Ipad Air 5th Gen Tablet. Currently My computer has this specs: CPU(s): 4 On-line CPU(s) list: 0-3 Vendor ID: GenuineIntel Model name: Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz CPU family: 6 Model...
  3. A

    Understanding CPU Frequency Waveforms and Dead Time in Modern Processors

    There was a thread recently in another subforums where a user talked about creating "square waves" at Ghz frequencies. It was said there that at that frequency range one cannot have a square wave as the inductance "rounds off" the edges making the waveform sine like. I am wondering then how...
  4. Wrichik Basu

    Google Chrome suddenly using lot of CPU & memory after update

    I just updated Chrome, and suddenly, my laptop's memory and CPU usage peaked. All 16 GB of memory was used up, and all CPUs were showing 100% usage. Everything came down to normal as soon as I closed Chrome. Here is a screenshot, taken some time after this peak usage: This is on Ubuntu...
  5. A

    Why is my CPU not running at max published speed?

    I have a Intel(R) Xeon(R) E-2274G CPU @ 4.00GHz 4.01 GHz machine which has a published max speed of 5.0 GHz. However, when I run it under load on all 4 cores, it only gets up to about 4.5 GHz: Could someone explain to me why it's not ramping up to the full 5.0 GHz or what I could do to...
  6. Mason_Jays

    How to design a CPU Cooler attached on an Aluminum Panel?

    Im now drawing sheet metal blueprints, which has a feature like attachable of Commonly use of CPU Cooler. The product that i want to attach is Cooler master Hyper T4. is there any information about standard dimension for regular cpu cooler installation ?
  7. M

    MATLAB What CPU, GPU, and RAM are recommended for efficient image processing in MATLAB?

    Hi PF! A friend of mine is starting her postdoc, where she will be using MATLAB for image processing (she might get into C too, unsure at the moment, as she just got the position a few days ago). Currently, each run uses about 2000 images, each at 2 MB. Given this, what CPU, GPU, and amount of...
  8. Z

    Calculating CPU Utilization with 5 Processes & 30% I/O Time

    Mod note: Initially posted in a non-HW forum section, so missing the template Summary:: Hi, I am trying to find CPU utilization What is the CPU utilization if there are 5 processes running at the same time, and on average the CPU spends 30% of its time waiting on I/O completion? The formula...
  9. M

    CPU Speed Test: How to Measure and Improve Your Processor's Performance

    Hi PF! I'd like to test how fast my cpu clock speed is. Any recommendations with benchmarks so I can see just where I fit?
  10. Z

    Building a CPU with Si JFETs: Fundamental Challenges?

    Would there be any fundamental reasoning (i.e. excluding cost, energy, and resources) that we could not build a modern day CPU using Si JFETs rather than Si CMOS? I realize the JFET device size would be huge, and the absences of enhancement mode JFETs may impact power consumption, but would...
  11. M

    Questions about the operation of this C68MX11 CPU

    Part (a) The Purpose of the Accumulators The accumulator is a register for short-term, intermediate storage of arithmetic and logic data in a CPU. (The term "accumulator" is rarely used in reference to contemporary CPUs, having been replaced around the turn of the millennium by the term...
  12. prashantakerkar

    Calculators Cooling fan for Smartphones CPU

    Is there a cooling fan with a heat sink on the Smartphones CPU - Quadcore processor and above similar to the desktop and Server CPU? If not, why?. Is it not required? Thanks & Regards, Prashant S Akerkar
  13. K

    Why is my CPU usage so high when opening multiple web pages on Microsoft Edge?

    I opened about 30 Microsoft Edge web pages.. the CPU usage can reach 75%. Why is there so much CPU usage for opened web pages? My processor is Intel Corei5 3.2 Ghz and 16 Gigs of DDR3 RAM.
  14. Wrichik Basu

    Changing the LAN card in a CPU

    There must be people here who remember me discussing about lightning affecting my neighbour's appliances. Now it seems that I am also a victim. But in my case, the problem is different: the lightning has come up through the cable of broadband connected to my PC, thereby burning the LAN card...
  15. W

    Heat transfer within a laptop computer from CPU and GPU

    Hello all I have a practical question regarding heat transfer within my laptop. My laptop uses a shared-heatpipe design, meaning that my CPU and GPU are connected by a common piece of copper, and then each chip goes off to its own heatsink/fan. While playing games, I was monitoring the...
  16. B

    Will there ever be a new CPU manufacturer?

    Currently in desktop CPU manufacturing, there are only 2 companies that hold practical all of market. I have read it is because Intel and AMD own licenses to x86 and x64 architecture ( Let's assume VIA is non-existent). Now if a new company wants to make CPUs they need to make some new CPU...
  17. N

    CPU Register Components: Buses and 1 Byte

    In a CPU there are eight wires (buses) connected to the register components. which means the data can travel 8 bits as a time ? if the register is 32 bit and the value i want to store in a specific register the data must be travel 4 times in a row and store the binary value to a register?
  18. fluidistic

    Exploring Data in the CPU Cache

    Hello, I wonder what kind of data usually go into the CPU cache. Generally the size of the cache is in kB or MB in contrast with RAM which is in GB. I understand that the cpu accesses the RAM much slower than the cache so it's better for it to find the data in the cache instead of in the RAM...
  19. manik hossain

    Is a Single CPU Fan Enough for 24/7 Use?

    Single fan is enough for 6800K? like Thermaltake CLW0222-B Liquid CPU Fan or Cooler Master SEIDON 120V Plus Liquid CPU Cooling Fan. I want a ans which better for me 2 fan cooler or single fan cooler? note: My PC should be RUN minimum 14h/day
  20. B

    What does the 1.00 GHz refer to in the description of my CPU

    My control panel gives the following description of the CPU or processor on my computer: AMD C-70 APU with Radeon(tm) HD Graphics 1.00 GHz What does the 1.00 GHz signify in the description of my processor? I know that 1.00 is a frequency that means 1.00 Gigahertz, but what in my CPU is...
  21. MathematicalPhysicist

    Understanding 10GHZ CPU Technology: Obstacles and Resources

    What are the current obstacles from having one core 10 GHZ CPU processor? What books/courses do you propose to read/take in order to understand the theory behind CPU technology? I assume how to cool such a processor is one of the obstacles, but there are more, right?
  22. F

    Bipolar Junction Transistor and CPU

    I am looking at the Bipolar junction transistor, but I cannot seem to correlate with how the design would work for the CPU in terms of 0 and 1s. I am looking mainly at the transistor diagram from Wikipeida https://en.wikipedia.org/wiki/Transistor. Can someone tell me what Vcc, Vin, and Vout are...
  23. G

    I'm curious about radiation effect from high speed cpu

    Hello. We're in the age of the high speed computation. Personal computer clock speed is on the order of GHz and scientist looks for a way to raise the speed up to THz class. I've read this from newspaper and got some question. I've learned in class that radiation effect becomes severe as...
  24. K

    Electrical Designing Your Own CPU Cooler Fan: Fundamental Tips

    Hi folks.I'm 3rd grade mechanical engineering student.I want to make cpu cooler.I will make pid controlled fan with an arduino. PID path is easy but I could not find anything about fan dynamics. I want to design my own fan.I need something like "fundamentals of fans" that should answer my...
  25. Delta2

    CPU power consumed relates to information processed?

    As far as i know CPUs consume power because of the ohmic resistance of the transistors that they are built of(i hope i am not wrong on this). But if we were able to build some sort of superconducting CPU with almost zero ohmic resistances, would it be able to operate and perform computations...
  26. Superposed_Cat

    How does the cpu work out greater than (>) in unsigned ints?

    Hey all, I understand how the cpu does most things but I can't figure out how it would work out greater than or less than in unsigned integers, in signed you could simply subtract them and check the highest bit for sign (I assume) but unsigned ints will loop back to the greatest value if A-B...
  27. Superposed_Cat

    Best circuit designing program for designing cpu?

    Hey all, what is the best software (free) that allows you to build virtual circuits and 'run' them? Something that could support large circuits, such as a cpu?
  28. N

    How does RAM give "4"th value when CPU requests the "001"th

    Hey all, I'm currently building a 8 bit CPU and ram in simulator software but have no idea how to call a specific memory cell, ie I can't call the "001"(binary) cell, I'd want it to be translated to call the 4th cell. How does real ram solve that issue? Any help appreciated, thanks.
  29. E

    Please recommend a high-performance CPU cooler with red LED

    Could someone please recommend a high-performance aluminum aftermarket CPU air cooler that has a red LED light?
  30. pairofstrings

    Software that shows how CPU registers are being used during execution

    Hello Can any Assembly Langauge guru help me remember a software name which shows how registers of CPU are being used after execution of each ASM instruction? I vaguely remember that there used to be 16-bit program which showed me names/title like AX BX CX DX and values underneath those titles...
  31. B

    Understanding CPU L3 Cache: Intel Core i3-2130 Specs and How It Works

    I have an intel core i3-2130 CPU and I ran the CPU-Z program to get the specs on it. It told me my L3 Cache was 3MB and my L2 was 256kB. Now for my L1 it gives it into lines like this L1 Data 32kB L1 Instructions 32kB. Now I would gess that my L1 is Divided into 2 Blocks of 32kB...
  32. B

    Understanding the Memory Hierarchy and Its Impact on CPU Performance

    I just was thinking somebody may be able to help me understand something about Computers. If I have a PC and the Memory in it is 1066 MHz I know the real Clock speed 533 MHz because DDR Dabbles the Data Rate. And if I have a CPU that is 2 GHz it is running at 2,000 MHz now this is what I...
  33. N

    Why do my programs keep coming up as NTVDM CPU illegal instruction?

    I am using Windows XP Version 2002 and I am using freecommandLinetools as a compiler for the c++ language. Every time I write a program it always says it is an NTVDM CPU illegal instruction and it doesn't work, what's wrong with my programs? Here is an example: #include <iostream> using...
  34. J

    Quad Core vs Dual Core: Which is Better for a Physics Major's Laptop?

    As a soon to be physics major I am about to purchase a laptop. However, I can't decide what I want. Should I go for a laptop with a dual core processor with a higher clock rate or a quad core processor with a slower clock rate. The laptop with the quad core is a bit out of my price range but I...
  35. F

    Solve RISC CPU Questions - Confirm Answers

    Hello, I am having some trouble with the following set of questions. I include them along with my answers. Would anyone be able to confirm if I am correct here ? Thanks kindly for any help. Suppose a RISC machine uses overlapping register windows for passing parameters between procedures. The...
  36. fluidistic

    Comparing a desktop cpu to a tablet cpu

    I'm wondering how to compare my desktop cpu to my tablet cpu. They are an intel core 2 duo E6300 (1.86 Ghz, you can see it at http://ark.intel.com/products/27248/) and the Samsung galaxy note 10.1, basically a quad core Exynos at 1.4 Ghz. I would have expected that when running a chess program...
  37. E

    Polled interrupts: how does the CPU know which ISR to run?

    Hello, may someone help me to understand this? I know that in vectored interrupts, a device asks the CPU to run a certain ISR by sending a specific code. Now, in polled interrupts there's no interrupt vector. So how does the CPU know what's the Interrupt Service Routine to be run? Perhaps...
  38. K

    PC game that uses more than four CPU threads?

    Are there ANY PC games that use more than four CPU threads? It's about time that computer games make use of hyper-threading and 6-8 core processors. I read somewhere that flight simulator X is coded to use up to 16 threads. Although I'm not sure if that's actually true.
  39. T

    CPU cooling - one fan vs. two?

    I have a question about fans and airflow, specifically related to processor cooling. I have a large heatpipe/radiator on my processor which came with one fan installed that blows air across the fins (a push fan). The assembly is set up to be able to add a second fan on the opposite side to...
  40. H

    Optimizing Soft Error Pulse Width for CPU Fault Injection

    Homework Statement Hi, I am trying to inject some faults into a CPU manually. But I am not sure what should the soft error (SET) pulse width should be? I know that is different in different case. Therefore, I am going to set up a random generator to generator the SET pulse width. But what range...
  41. D

    Why Do Engineering Associations and Registries Exist?

    Is it possible for someone to learn electrical engineering and work in the industry? How common is this? I mean coming from a the software industry I know that there are many including innovative ones are self-taught and have no degrees. Does this apply to engineering as well? How would it...
  42. D

    Fastest Single Core CPU 2012?

    is there still single core cpus still in production?, before people start saying use multicore etc I've already explored this and the reason behind my unusual question is that I am trying to run an old game server on my pc, however it will not run on multi core systems the usual solution which i...
  43. D

    Physical CPU Circuitry Referencing Memory

    How does a CPU send information to memory locations - physically? I know in software you can reference memory locations. I'd like to know how a CPU references them? I understand that it symbolizes a memory location using bits (00000101 = 5) but - how does that string of bits work in the...
  44. K

    Microprocessor vs CPU: What's the Difference?

    Hello Is microprocessor =cpu use in PC? what's the difference between the two? wiki says microprocessor is a part of cpu used in personal computer, so I guess Mac doesn't use microprocessor? thx
  45. P

    Question regarding Pentium 4 CPU and bus

    Homework Statement Why is it impossible for Pentium 4 to work in a 32-bit PCI bus without loosing any functionality? After all, other computers with a 64-bit data bus can do transfers of 32, 16 and even 8 bits wide. Homework Equations The Attempt at a Solution I'm not sure what loss of...
  46. H

    What's wrong with my Q550 atom CPU?

    What's wrong with my Q550 atom CPU?? I brought a Fujitsu Q550 one week ago from J&R via Amazon. I would like to use it with Onenote for jotting note during class However, it is running very slow, I would barely use the Onenote alone, can't open any other pdf ebook at the same time, otherwise...
  47. E

    How do disk operations affect CPU utilization?

    How much is the CPU involved in disk operations. Let's say I have a long disk operation such as copying a large file for several minutes. When I look at the CPU utilization on my computer (Windows XP), it's pretty low; basically zero. So how involved in such an operation is the CPU? Does it just...
  48. H

    PC cpu limitation ruining our movie promise

    Hi, I'm new here. My colleague and I are working on a sci-fi movie script. It's almost finished and it's going very well, thanks. At the beginning we made a promise. Although there inevitably has to be some small fantasy elements to any sci-fi story, we promised each other we wouldn't...
  49. J

    Exploring the Mystery of CPU Transistors and Performance

    Hi, I'm confused about something. Why is it that in magazines and videos it seems as though adding more transistors to a CPU will make it faster? Is it a numbers thing (like, instead of marking amps on signs, they show volts)? I mean, I understand that you can do multithreading, multiple...