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PowerNow!

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AMD PowerNow!
Design firmAdvanced Micro Devices
IntroducedApril 2000
TypeDynamic frequency scaling technology

AMD PowerNow! is AMD's dynamic frequency scaling and power saving technology for laptop processors. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, reduce heat and noise. The lifetime of the CPU is also extended because of reduced electromigration, which varies exponentially with temperature.[1]

The technology is a concept similar to Intel's SpeedStep technology. The adaptation of PowerNow! for AMD's desktop CPUs is called Cool'n'Quiet. Newer Opterons also use an adaptation of PowerNow! called Optimized Power Management.

AMD has supplied and supported drivers for its PowerNow! technology that work on Windows 98, ME, NT, and 2000.[2][3]

Processors supporting PowerNow!

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Version

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PowerNow! 1.0

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The technology first appeared in both AMD K6-2E+ and K6-IIIE+ processors.[4][5] PState circuit switching was just programming (software) via I/O, it was slow and technologically obsolete. The multiplier change may have been even more than 1 multiple of the multiplier (1 step), this could have caused unstable conditions at large frequency difference, due to the unsynchronization of the internal oscillator frequency.[6] Consequently, it was necessary to keep the frequency unchanged for a certain period of time to stabilize the oscillator and processor operation.

PowerNow! 1.2

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Improved version of the original technology. It first appeared for AMD Athlon 4Mobile Athlon XP-M and Duron mobile processors.[7][8][9] PState mode switching was controlled programmatically via MSR, which was faster and more technologically advanced.[10][11] The change in multiplier was still probably more than one step.

PowerNow! 1.4

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Improved version of the technology. It first appeared in the AMD K8 core (AMD Athlon 64, etc.).[12][13] The switching of PState circuits was still done through the MSR. The multiplier can be changed by only 1 step, this allowed for faster frequency changes and better function savings. The downside was the inability to set the multiplier to a minimum value between 5× and 7× for some processor models.

See also

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Power Saving Technologies:

Performance Boosting Technologies:

References

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  1. ^ "AMD PowerNow!™ Informational White Paper" (PDF). Retrieved 27 August 2021. AMD.com – TechDocs
  2. ^ AMD Turion 64 X2 Dual-Core Mobile Technology Utilities & Updates, Advanced Micro Devices, retrieved 2007-04-30
  3. ^ AMD Turion 64 Mobile Technology Utilities & Updates, Advanced Micro Devices, retrieved 2007-04-30
  4. ^ "AMD PowerNow!™ Technology Informational White Paper" (PDF). www.amd.com. Retrieved 2024-08-12.
  5. ^ "AMD embedded processor line hits 550 MHz". www.edn.com. Retrieved 2024-08-12.
  6. ^ "CPU multiplier jumping up and down". linustechtips.com. Retrieved 2024-08-12.
  7. ^ "AMD Mobile Processors". flylib.com. Retrieved 2024-08-12.
  8. ^ "What AMD's PowerNow! power reduction technology is all about". refurbisheddubai.ae. Retrieved 2024-08-12.
  9. ^ "Guide to PowerNow! – AMD's dynamic power management technology". www.pctechguide.com. Retrieved 2024-08-12.
  10. ^ "AMD 2nd Gen EPYC CPU Tuning Guide for InfiniBand HPC". hpcadvisorycouncil.atlassian.net. Retrieved 2024-08-12.
  11. ^ "RyZen Pstate Overclocking, method, calculation and Calculator". hardforum.com. Retrieved 2024-08-12.
  12. ^ "BIOS Requirements for AMD PowerNow!™ Technology Application Note" (PDF). doc.xdevs.com. Retrieved 2024-08-12.
  13. ^ "What does AMD Application Power Management (APM) and HPC Mode BIOS Settings do?". www.ronwoods.us. Retrieved 2024-08-12.
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