Is it possible to down-clock a laptop CPU, i.e. make it slower?

Rationale: I’d like to save battery power and generate less heat.

My laptop is an HP Compaq 6715b running Windows 7 Professional SP1, 32-bit. The CPU is an AMD Turon 64 X2 Mobile TL-60.


Most more or less modern laptops adjust their CPU clock constantly, so I think what you really want is to limit the maximum frequency allowed:

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  • My minimum processor state is 0%. If this truly means Windows can reduce the CPU to 0Hz when idle, that means the CPU can't run any more instructions - then how does it come back to a normal state!? – BlueRaja - Danny Pflughoeft Jun 14 '12 at 15:20
  • @BlueRaja that case would be true if the Maximum processor state could be set to 0%. Having the minimum limit means it can drop that low, but it never has to stay there. Setting the Maximum that low would be something that could in theory keep it from running. But the minimum state... that wouldn't keep it from running. What I'd wonder about, is what happens when the minimum is higher than 0%? What is the computer doing THEN when idle? What is done to keep the CPU at at least the minimum processor state? – Bon Gart Jun 14 '12 at 15:28
  • @Bon To answer your question: en.wikipedia.org/wiki/Idle_%28CPU%29 but you seem to misunderstand my question. If the CPU is running at 0Hz, it can't run any instructions. That means the OS can't do anything. At all. But if the OS can't do anything, how does it instruct the CPU to increase the clock speed again? There must be an interrupt, or something, which means the clock is not actually running at 0Hz. I have a feeling that reducing the maximum does not actually reduce the clock speed, it just reduces the min-running time of the idle process.. – BlueRaja - Danny Pflughoeft Jun 14 '12 at 15:50
  • @BlueRaja While 0% might not necessarily mean 0Hz, it's not inconceivable. The OS might configure a timer to cause an interrupt, say, 100 times a second, and then just halt the CPU (which approximates 0Hz). When the interrupt occurs, it checks if there's any work to do, and if so, updates the clock frequency. – RomanSt Jun 14 '12 at 20:30
  • if you set it 0Hz.....who is gonna show your mouse cursor moving? 0Hz means it is off! like when you shut down... and mind you 0% and 0Hz are totally different things. you should monitor using cpu-z to see how your cpu clock is adjusted automatically. – tumchaaditya Jun 18 '12 at 9:44

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