Chapter 4 Processor

							                                         Chapter 4
                                           CPU
Objectives
  1. Students will be able to identify different types of processors.
  2. Students will be able to explain processing speed and system bus speed.
  3. Students will be able to explain the purpose of memory cache.
  4. Students will be able to explain the difference between Level 1 cache and Level 2 cache.
  5. Students will be able to explain the purpose of cooling fans and heat sinks.
  6. Students will be able to locate and identify a CPU, heat sink, and cooling fan.

The Pentiums
    The most popular CPU made by Intel.
    Pentium processors have 2 ALU’s, so it can process two calculations at once.
    Contains a 64 bit external path size, and a 32 bit internal path size.
    Recall bus speed:
          o The frequency or speed at which data moves on a bus.
          o Motherboard bus, system bus, is the fastest bus and connects directly to the
              CPU.
                   Also called the host bus because other buses connect to it.
                   Also called the memory bus because it connects the CPU to RAM
                      memory.
                   Also called the FSB because it connects to the front side of the CPU,
                      which faces the outside world.
          o Common speeds for the system bus are 100 MHz, 133 MHz, 200 MHz, 400 MHz,
              533 MHz, 800 MHz, and 1066 MHz.
    Processor speed is the speed at which the CPU operates internally.
          o If the CPU operates at 3.2 GHz internally, but 800 MHz externally, the processor
              speed is 3.2 GHz and the system bus speed is 800 MHz.
                   In most cases, the CPU operates 4 times as fast as the system bus, which is
                      called the multiplier.
                           System bus X Multiplier = Processor speed
          o Newer motherboards automatically detect the processor speed and will adjust the
              system bus speed accordingly.
    Memory cache is a small amount of RAM (Static RAM or SRAM) that is much faster
      than other RAM, which is called Dynamic RAM or DRAM.
          o SRAM is faster than DRAM because SRAM does not need refreshing and will
              hold data as long as power is available.
          o The CPU can process information faster if the data is temporarily stored in SRAM
              cache.
          o Level 1 Cache (Internal cache, Primary cache) – memory cache on the CPU.
          o Level 2 Cache (External cache, Secondary cache) – cache outside the CPU.
                   Usually 128 K, 256 K, 512 K, or 1 MB in size.
    Refer to Table 4-3 on page 134 for a list of Pentium processors.

Celeron Processor
    Low end Pentium processor that targets low end PC multimedia.
      Uses Level 2 cache within the processor housing.

Pentium III Processor
    Runs with a 100 MHz or 133 MHz system bus.
    Processor speed up to 1.33 MHz.

Pentium 4 Processor
    Currently runs up to 3.8 GHz.
    Later Pentium 4 processors come with Hyper-Thread Technology, which executes two
      threads in parallel to improve multitasking performance.
          o The motherboard and processor must support Hyper-Thread Technology for it to
             be effective.

AMD Processors
   Refer to Table 4-4 for a list of AMD processors.
   Athlon XP is a popular AMD processor.
        o Comparable to a Pentium 4 processor.
        o Runs at a speed up to 2.2 GHz.

CPU Heat Sinks and Cooling Fans
   CPU’s generate a lot of heat, and need a cooling fan to keep temperatures below the Intel
     maximum limit of 85 degrees Celsius.
   A good cooling fan will maintain a temperature of 32 – 43 degrees Celsius.
   Many high end systems will have more than one cooling system.
   Cooling fans usually fit on top of the CPU.
   The fan is equipped with a power connector that connects to the power supply.
   Older computers use a heat sink.
         o A heat sink is a clip on device that mounts on top of the CPU.
         o Little fingers or fins pull heat away from the CPU.
   Some computers will have a heat sink and a cooling fan.
   Refer to figure 4-11 on page 142.