CPU - types, speed, performance

• the CPU understands only binary code that is 0 & 1. the CPU has two primary measures of speed :
  • integer Rate
  • Clock Rate

• Computer commands are essentially just on and off commands, represented by one and zero, respectively which is binary code.

• the integer rate describes how many on and off commands a CPU can handle at one ime.

• Interger Rate Example
  • An 8-bit CPU can handle eight on and off commands at a time, whereas a 64-bit CPU can handle 64 on and off commands at a time.

• Clock RATE : the Clock rate simply refers to how many times the integer rate can repeat in a second. the higher the clock rate, the faster the CPU.

• the CPU performance:
  • there are four key facotrs about CPU architecture that affect the CPU performance
    • No or Cores(CORE = ALU + CU + Registers)
    • CLock speed
    • Cache Memory Size
    • Processor type.

• CORES(CORE = ALU + CU + Registers)
  • First generation CPUs had a single core. that means the CPU had only one core inbuilt in to the processor chip
  • to increase the CPU performance, the manufactures added additional “cores” or central processing units. A dual-core CPU has two central processing units, so it appears to the operating system as two CPUs.
  • A different process can use each core at the same time. this speeds up our system considerably, because computer now process multiple programs simultaneously.
  • it is coomon for computers to have two(dual), four(quad) or even more cores. CPUs with multiple cores have more power to run multiple programs at the same time.
  • the clock spped is imporatant measure of speed of processor. the clock speed of a processor is how fast the processor can do the tasks while executing a program. the clock speed is measured in megahertz(MHz) or GigaHertz(Ghz).
    • 1 MHz - One Million clock ticks every second
    • 1 GHz - One billion clock ticks every second
  • this means that if one instruction was carried out every clock tick, a 3 GHz processor could execute three billion instructions for three billion clock ticks every second.

• A CPU can contain more than one core. however, by simply doubling the number of cores will not double a computer’s processing speed. the CPU cores have to communicate with each other through channels and this uses some processing time of the CPU cores.
• Multi-Channel memory architecture is a technology that increases the data transfer rate between the DRAM memory and the memory controller by adding more channels of communicatation between them. theoretically this multiplies the data rate by exactly the number of channels present.

• processor types:
  • there are two main types of CPU
    • CISC - Complex instruction set computing
    • RISC - Reduced instruction set computing
  • Most desktop or laptop computer use CISC(Complex Instruction Set Computing) architecture made by Intel or AMD.
  • whereas Smartphones and tablet use RISC by ARM architecture