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Thread: Best 500/600W semi passive PSU?

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    As I understand it the power goes in proportion to the clocking frequency, but in the case of a CPU does anyone know if there is a simple relation between the core voltage and power dissipated?
    Last edited by ashiekh; 08-08-2019 at 05:59 PM.

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    Quote Originally Posted by strumf666 View Post
    https://www.techspot.com/review/1883...adeon-rx-5700/
    5700XT becomes quite inefficient, when sufficiently overclocked.
    Well, d'uh, cpt. Obvious is calling.
    That's almost always the case when Overclocking, especially with modern components...

    And modern, "intelligent" power/clock regulating mechanisms.

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    Quote Originally Posted by ashiekh View Post
    As I understand it the power goes in proportion to the clocking frequency, but in the case of a CPU does anyone know if there is a simple relation between the core voltage and power dissipated?
    iXBT made a power consumption vs. CPU Clockrate article a while back, sadly they are offline so I can't link it.

    As I remember, the power consumption exploded as soon as you increased the voltage. The i7-860 and 920 (IIRC) almost or more than doubled their power consumption with increased voltages...

    And in modern cases, we often talk about +50% power consumption for 10-15% higher clockrates...

    But that's been the case for a long long time!

    From 4,5 to 5GHz looks amazing but that's just 11% more...

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    ashiekh (08-08-2019)

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    There is a power curve. As you increase Vcore, the temp goes up in a more-or-less linear fashion until it hits an inflection zone. Then the temp soars. When you hit that inflection, it is time to stop overclocking.
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    As Stefan said with modern hardware power consumption is more dependent on frequency increase than voltage increase, but certainly both increase power draw and heat.

    Quote Originally Posted by Stefan Payne View Post
    Well, d'uh, cpt. Obvious is calling.
    That's almost always the case when Overclocking, especially with modern components...

    And modern, "intelligent" power/clock regulating mechanisms.
    In some more, than other... Vega is pushed into inefficient zone from factory, but you can still get some additional performance with overclocking and increased power draw, 5700xt looks to be in comfort zone from factory, but when you overclock you don't get a lot of performance increase, mostly just increased power draw.

    Quote Originally Posted by ashiekh View Post
    As I understand it the power goes in proportion to the clocking frequency, but in the case of a CPU does anyone know if there is a simple relation between the core voltage and power dissipated?
    Probably quite dependent on the cpu architecture.
    Last edited by strumf666; 08-08-2019 at 08:14 PM.
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    Switching losses increase linearly with clock frequency. However, increased voltage is often required to increase clock speed and voltage will generally increase power consumption quadratically.

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    Quote Originally Posted by ehume View Post
    There is a power curve. As you increase Vcore, the temp goes up in a more-or-less linear fashion until it hits an inflection zone. Then the temp soars. When you hit that inflection, it is time to stop overclocking.
    Even with Resistor, the voltages influences it quadratic -> double the voltage = 4 times the power because double the Amperage as well.

    And that's not with semi conductors wich are weird as hell and a couple of hundreds of millivolt can mean +50% power consumption...

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    Superflower LEADEX III is also super quiet... if you can grab one.

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    Quote Originally Posted by Stefan Payne View Post
    Even with Resistor, the voltages influences it quadratic -> double the voltage = 4 times the power because double the Amperage as well.

    And that's not with semi conductors wich are weird as hell and a couple of hundreds of millivolt can mean +50% power consumption...
    I thank you for the information. In addition, it seems CPUs are more complicated than simple temps and power consumption: I got more GFlops done if I lowered the frequency (and Vcore needed to sustain it) to keep the core temp at 80c or less. And if you are at the inflection point, sometime a couple of hundreds of millivolt could get you way more than +50% power consumption increase.
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  14. #30
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    How right you guys are

    https://en.wikipedia.org/wiki/Overclocking

    "Increasing the operation frequency of a component will usually increase its thermal output in a linear fashion, while an increase in voltage usually causes heat to increase quadratically."

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