computer science

PowerNow!

PowerNow! is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand PowerNow! rather than just read about it. In short: AMD PowerNow! was AMD's dynamic frequency scaling and power saving technology targeted at mobile and embedded microprocessors. It allows for the core voltage and frequency to be controlled on-the-fly by the host operating system, or BIOS for embedded systems.

PowerNow! — illustration

Key takeaways

PowerNow! belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PowerNow! to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PowerNow! from memory before moving on to harder problems.

Reference excerpt

AMD PowerNow! was AMD's dynamic frequency scaling and power saving technology targeted at mobile and embedded microprocessors. It allows for the core voltage and frequency to be controlled on-the-fly by the host operating system, or BIOS for embedded systems. PowerNow! was introduced with AMD's embedded processors using their K6 architecture, with the goal to combat the ever-increasing power demands and heat output with microprocessors at the time. The technology is similar in concept to Intel's first generation SpeedStep technology. However, at the time PowerNow! was released, Intel's SpeedStep only allowed the system to step between two predefined states for core voltage and frequency (high and low). This is in contrast to AMD's implementation which allowed for up to 32 customizable settings for core voltage and frequency, with steps as small as 25 or 50 mV and 33 to 55 MHz respectively. The core frequency itself can also be controlled independently. Though PowerNow! was originally designed with mobile and embedded systems in mind, it was adapted for use in desktop and server applications with the advent of Cool'n'Quiet and Optimized Power Management respectively. All three of these technologies aimed to complete the same goal for different segments of the market. PowerNow! as a feature was supported on AMD's server and desktop microprocessors and were not exclusive to embedded or mobile systems. It was retired and succeeded by AMD's SenseMI's Pure Power feature in 2017 with the introduction of the first generation Zen architecture.

Processors supporting PowerNow! K6-2+ K6-III+ Athlon XP-M - some models. Mobile Athlon 64 Mobile Sempron Turion 64 and X2 Athlon II AMD Accelerated Processing Unit

See also Dynamic frequency scaling Power Saving Technologies:

AMD Cool'n'Quiet (desktop CPUs) AMD PowerTune (graphics) Intel SpeedStep (CPUs) Performance Boosting Technologies:

AMD Turbo Core (CPUs) Intel Turbo Boost (CPUs)

References

External links AMD PowerNow!

Worked examples

Example 1 — a first encounter with PowerNow!

Start with the simplest possible case. Write down what PowerNow! claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to PowerNow! before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about PowerNow! ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of PowerNow!

In research: PowerNow! appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses PowerNow! in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: PowerNow! is common in secondary-school and first-year university syllabi. It links to neighbouring topics AMD technologies, Computer-related introductions in 2000, Computer hardware stubs, so understanding it makes those chapters shorter.
In everyday life: Look for PowerNow! outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study PowerNow! in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PowerNow! means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain PowerNow! out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PowerNow! in simple terms?

Why does PowerNow! matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study PowerNow!?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on PowerNow!.