Clock speed

3 Key excerpts on "Clock speed"

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  eBook - ePub

  Programming for Problem-solving with C

  Formulating algorithms for complex problems (English Edition)

  • Dr. Kamaldeep(Author)
  • 2023(Publication Date)
  • BPB Publications

    (Publisher)

  The Clock speed refers to the rate at which the CPU can execute instructions. It is measured in Hz (Hertz). A clock governs CPU operation. The CPU retrieves and carries out one instruction with each tick of the clock. Cycles per second are the unit of measurement for the speed of the clock, and one hertz is equal to one cycle per second. When a CPU has a greater Clock speed, it can process instructions at a faster rate. Processor running at 3.6 GHz executes 3.6 billion cycles per second. The speed of the older processors was measured in megahertz millions of cycles per second).

  The total number of processor cores

  The CPU is comprised of an element known as the core. A CPU typically consists of a single-core processor. Most contemporary central processing units feature two, four, or even more cores. For instance, a dual-core CPU contains two cores, whereas a quad-core CPU contains four cores. A single-core processor can only fetch and carry out one instruction at a time, whereas a dual-core processor can fetch and carry out two instructions at a time. A CPU with four cores can execute even more instructions in the same amount of time than a processor with only two cores.

  Cache memory

  A cache is a short-sized memory that operates at a very fast speed and is located on the CPU. It contains the data and instructions that are used again and again. The larger the cache is, the faster the frequently used instructions and data may be transferred into the processor and utilized. This is because more space is dedicated to storing them in the cache.

  The memory unit

  Memory units are responsible for not only storing data but also instructions or programs. The data and the program are both retrieved from memory by the central processing unit (CPU), which then performs operations on them (processes them). If there are any intermediate results produced, these will also be preserved in memory. The final result that is generated by the CPU is saved in the memory. Figure 2.7

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  eBook - PDF

  Computer Systems Architecture

  • Aharon Yadin(Author)
  • 2016(Publication Date)
  • Chapman and Hall/CRC

    (Publisher)

  So for measuring or comparing execution times of different appli-cations that were run on the same system, the number of cycles (or the number of beeps) is sufficient, since in all these cases it is the same clock frequency . This understanding can be easily proved mathematically. The processor time is defined by the number of seconds required to run the application. This time is calculated by the number of cycles required for running the application multiplied by the cycle time Processor time Seconds per application Seconds Applicatio = n       Seconds Application Cycles Application Seconds Cycle = * Table 4.2 is provided for better understanding the time names. The left side refers to the clock rate while the right side refers to the appropriate number of cycles. “Iron Law” of Processor Performance Although for various users, the term performance may have different meanings, the most common definition relates to the response time obtained by the system. However, this time includes the time required to perform the specific task (execute the program) as well as other time-consuming activities that might be needed, such as input, output, and Cycle time Transfer data from origin register Result is at the destination register Fixed signals to synchronize stat of operations FIGURE 4.21 Clock time. 120 ◾ Computer Systems Architecture communication. In this section, we will concentrate only on the processor performance, that is, the amount of time required by the processor to perform a specific task (or pro-gram).

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  Hardware and Computer Organization

  • Arnold S. Berger(Author)
  • 2005(Publication Date)
  • Newnes

    (Publisher)

  We can see that the deck is really 398 Performance Issues in Computer Architecture stacked against the 8-bit SBC. For starters, the PC clock is 200 times faster than the SBC clock. Now, we need to be a little cautious here because the PC clock rate is the internal clock rate of the CPU. The external memory typically clocks at 200 MHz for PC3200 DDR memory. f^mnieter Clock speed Data bus width Addressable memory Clocks per instruction Floatinq point calculations Cache External memory Graphics acceleration PC 2.000 MHz 32-bits 4,096 MB <1 In hardware On-chip 1 cache and D-cache 256MB On video card SiC 10 MHz 8-bits 32MB 8-20 None None 32MB None €(Milltl0lit CPU on PC has multiple pipelines FPU on-chip Not a factor Also, external PC memory will be SDRAM, so there is a penalty of several clock cycles each time it does a burst memory load. However, the on-chip caches keep the external memory loads to a minimum. We can't say exactly what the cache hit ration is, but 90% is probably a fair guess. Can we thus make the assumption that a faster clock equates to better performance? In this case it certainly is a significant factor, but can we make the general statement that faster Clock speeds equate to better performance? An Intel Pentium 4 processor with a 3.2 GHz Clock speed and an AMD 3000+ Athlon processor have similar performance results on comparative benchmarks, but the Athlon's actual clock frequency is approximately 2.2 GHz. This created a perception problem for AMD. For most PC purchasers, the clock frequency equates to performance^ In order to remain competitive, AMD was forced to use a virtual clock frequency rating of 3000+. It is virtual because it means that the AMD part performs a bit better (the +) than the comparable Pentium processor running at a true clock frequency of 3,000 MHz.

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