Power Management

Which describes CPU turbo operation (such as Turbo Boost)?

  1. AAutomatically raising frequency above the rated value to boost performance when power and temperature allow
  2. BAlways running at minimum frequency to save power
  3. CAttaching a tiny jet engine to the CPU
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Answer: A. Automatically raising frequency above the rated value to boost performance when power and temperature allow

A CPU's rated frequency is set so that power and thermal limits hold even with every core heavily loaded. In practice there is headroom when only some cores are busy or the chip is cool. Turbo operation monitors power, temperature and current and raises frequency and voltage to use that headroom for more performance, automatically backing off when it runs out.

  • A. Correct. It converts headroom into performance.
  • B. That is power-saving operation.
  • C. Of course no engine is attached.
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More Power Management questions

  1. Which describes thermal throttling?
  2. Some CPU power limits let the chip run above the long-term average limit (close to TDP) for short periods. Why does this work?
  3. What is the most suitable use of features such as Intel RAPL that let software measure CPU and memory power and set caps?
  4. Which describes ACPI, used in PCs and similar systems?
  5. In smartphone SoCs combining high-performance and efficient cores, why does running light work on the efficient cores use less energy?