CPU notes

Central Processing Unit (CPU)

• Brain of the computer

• Its primary function is to execute instructions, perform calculations, and manage the overall flow of information within the system.

• Physical Composition:

  • Made mainly of Silicon (from sand), which is a semiconductive

  • Contains billions of tiny transistors.

  • Transistors are one way switches, controlling the flow of electrical current with binary code "ON" or "OFF" (1 or 0)

  • (How (PU made)

  • Ultra volmert Rothery!

Main Components of a CPU

• Control Unit (CU):

  • Responsible for interpreting program instructions.

  • Directs and coordinates the operations of the processor.

• Arithmetic Logic Unit (ALU):

  • Performs all arithmetic operations (e.g., addition, subtraction, multiplication, division).

  • Handles logical operations and comparisons (e.g., AND, OR, NOT).

• Memory Unit (e.g., Registers):

  • High-speed storage locations located directly within the CPU.

  • Used to temporarily hold data and instructions that are actively being processed, allowing for quick access.

Key CPU Features

• CPU Core:

  • The processing unit of a CPU that reads and executes program instructions.

  • Modern CPUs often have multiple cores to handle more tasks simultaneously.

• Hyper-threading:

  • Allows a single physical CPU core to act like two logical processors to the operating system.

  • This means the core can process two sets of instructions concurrently, increasing performance

  • Happens virtually

• Cache:

  • An extremely high-speed, short-term memory (RAM)

  • Significantly reduces latency.

  • For high priority processes.

• Thermal Throttling:

  • A microcode safeguard for the CPU to avoid overheating.

  • Happens when the CPU's internal temperature exceeds goes over a safe operating threshold (usually around 100^\circ C).

  • This process automatically reduces the CPU's clock speed and shuts down components so they aren't at risk of breaking down or blowing up

CPU Cores VS Clock Speed

• Clock Cycle / Speed:

  • The time it takes to send AND receive a calculation

  • In other words, the number of cycles the CPU can execute per second

  • "Fetch and retrieve"

• Multiple Cores:

  • Allows for multitasking

  • Or enables a single program to split calculations among multiple cores

CPU Instruction Set

• Instruction Sets are premade collections of machine (binary language) code.

• Allows the operating system / programs to ”call” on when needed

Socket Types

• Pin Grid Array (PGA):

  • Has the pins located directly on the CPU

  • If the CPU pins are damaged, typically only the CPU needs to be replaced.

• Land Grid Array (LGA):

  • The pins are on the motherboard socket, rather than on the CPU.

  • If the motherboard pins are bent or broken, a replacement motherboard is needed.

Binning

• Binning is a process that sorts CPU chips based on their performance and quality.

• This allows manufacturers to put chips into different product tiers

How to pick which CPU to use

• For applications like Photoshop, video editing, music production:

  • Multiple cores are used because it can distribute work across several processing units.

• For gaming:

  • Faster individual cores (higher clock speed) are used, since games prioritize single-core performance