cpu

• CPU


  Central Processing Unit, the most important component on the motherboard that controls and directs all the activities of the computer
• Facts about today's CPUs

  • The bulk of today's CPUs are 64-bit
  • 64-bit CPU architecture incorporates 64-bit wide registers that allow the CPU to work with and process 64-bit data types and provide support for address space in the terabytes
  • 64-bit CPUs have been available for PCs since 2003
  • Examples of 64-bit CPUs include the AMD FX and Intel Core CPUs
  • The predecessor to the 64-bit CPU was the 32-bit CPU
  • Intel started developing 32-bit CPUs as early as 1985 with the 386DX CPU
  • AMD developed 32-bit CPUs in 1991 with the Am386
  • A 32-bit CPU can't support nearly as much address space as a 64-bit CPU, limited to 4 GB
  • Most editions of Windows are available in both 32-bit and 64-bit versions
• Processor


  The most important component on the motherboard, controls and directs all the activities of the computer, a small silicon chip consisting of an array of millions of transistors
• Processors


  • Identified by characteristics such as hyperthreading and virtualization support
  • Key characteristics are architecture, speed and cache size

  
• Architecture


  • Processors are labeled as 32-bit or 64-bit which refers to the set of data lines between the CPU and the primary memory of the system
  • Another way to discuss architecture is describing the number of cores a processor has such as dual-core or quad-core

  
• Speed


  • Measured in Hertz (Hz) which means electrical cycles per second
  • Modern processors operate at billions (gigahertz, GHz) of cycles per second
• CPU Cores


  • In a single-core processor, the performance is limited by the time taken to communicate with cache and RAM, approximately 75% of CPU time is used waiting for memory access results
  • Multi-core processors can perform significantly better than single-core CPUs of the same speed
  • Multiple cores allow PCs to run multiple processes at the same time with greater ease, increasing performance when multitasking or under the demands of powerful apps and programs

  
• CPU Core


  • A CPU's processor
  • Though CPUs used to operate with just a single core, modern-day processors are predominantly multi-core, with at least two or more cores installed onto an integrated circuit die (or multiple chiplets), and can therefore process two or more tasks simultaneously
  • Processor cores are individual processing units within the CPU that receive instructions from a single computing task, working with the clock speed to quickly process this information and temporarily store it in RAM

  
• Each core can only execute a single task at a time
• Intel uses the term "Core" to brand some of its CPUs (ex: Intel Core i7-7500U processor)

  
• Processor types based on number of cores

  • Dual-core
  • Quad-core
  • Hexa-core
  • Octa-core

  
• Context Switch Overhead


  The performance penalty incurred when the CPU's cores are insufficient for the number of tasks being processed, as one task must be removed and the next task must be loaded

  
• Core Clock Speed


  • A measure of a core's processing frequency, not necessarily a measure of its overall performance
  • The number of cycles the CPU executes per second, measured in GHz (gigahertz)
  • During each cycle, billions of transistors within the processor open and close
• A CPU with a clock speed of 3.2 GHz executes 3.2 billion cycles per second
• Sometimes, multiple instructions are completed in a single clock cycle; in other cases, one instruction might be handled over multiple clock cycles
• CPU clock speed is a good indicator of processor performance, though applications like video editing and streaming rely more on multi-core performance, and many new video games benchmark best on CPUs with the highest clock speed
• Active Workloads


  Processes that need the user to manually manipulate or adjust data in real-time, such as interacting with an application's viewport in motion design, 3D modeling, video editing, or gaming, which are more dependent on high single-core performance and boost clock speeds
• Passive Workloads


  Tasks that are usually easily parallelizable and can be left unattended, such as CPU or GPU rendering, 3D rendering, and video rendering, which benefit from high core counts and higher base clock speeds

  
• Thread


  • A set of data sent from an application to the CPU to be processed
  • Threads are not physical components of the CPU, but rather an indicator of the amount of processes the cores can handle
  • Threading creates multiple virtual cores out of each physical core (usually two threads per core) to optimize task queueing and utilize the real core more efficiently

  
• Hyperthreading


  • The process of splitting physical cores into virtual cores, allowing a single core to process multiple threads more efficiently
  • It is essentially a way of scheduling threads to be executed by the core without any downtime, by readying a thread to be processed while another thread is being executed

  
• Logical Processors


  A measure of how many cores the operating system sees and can address, which is the product of the number of physical cores and the number of threads each core can handle
• Physical cores are more valuable than logical processors (threads), as logical processors at most will introduce a 50% performance uplift in well-parallelized workloads, while physical cores will show a 100% performance increase

  
• CPU Name Structure


  • There are five parts: Brand, Tier, Generation, Model, and Suffix (optional)
  • Examples: Intel Core i5-11400F, AMD Ryzen 5 5600G
• Brand


  The brand of the CPU, which is often omitted when specifying a CPU since the tier includes a brand-specific term
• Tier


  There are four processor tiers within each brand, indicating the relative performance and features of the CPU
• With two Hands (two threads), the second hand can already place food into the mouth to be processed while the first-hand looks for more food
• CPU Name Structure


  • Brand
  • Tier
  • Generation
  • Model
  • Suffix (Optional)
• CPU Name Structure


  • Intel's Core i5-11400F
  • AMD's Ryzen 5 5600G

  
• Brand


  When denoting a specific CPU, people will sometimes specify the brand, although this is largely unnecessary
• Tier


  A general indicator of performance; a higher tier number will indicate a more powerful and more expensive processor
• Tiers


  • 3
  • 5
  • 7
  • 9
• Intel Tier Naming


  Core i3, Core i5, Core i7, Core i9

  
• AMD Tier Naming


  Ryzen 3, Ryzen 5, Ryzen 7, Ryzen 9
• Intel and AMD processors within the same tier should have comparable performance, assuming they're from the same general time period
• Tiers Outside of Cores and Ryzen Lines

  • Pentium
  • Celeron
  • Threadripper
• Generation


  Indicates the age of the CPU
• Intel is currently on its 13th generation of processors, while AMD is on its 7th

  
• Model


  Gives the most exact idea of performance, at least within a specific generation
• Model Number Ranges


  • Under 400: i3/Ryzen 3
  • 400-600: i5/Ryzen 5
  • 700-800: i7/Ryzen 7
  • 800-950: i9/Ryzen 9
  • Over 950: Threadripper (AMD Only)

  
• Suffix


  Indicates something out of the ordinary about the CPU