ThrottleStop undervolt - higher VRM temps?

Discussion in 'Windows OS and Software' started by B0B, Feb 27, 2018.

  1. B0B

    B0B Notebook Consultant

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    Someone on the channel made this comment in my recent video

    "DO NOT use CPU UV 24/7, it is not good for the motherboard. CPU runs cooler yes, but it stresses the VRM on the motherboard more and if the VRM cooling is not good enough you will get microstuttering because the VRMs are overheating and in the long term your mb may die."

    We had a brief discussion and I began to research this. I found a few posts out there that have asked about this same thing. Not much was resolved from these topics and research seems limited to its defense.

    What are your thoughts?

    If you would like to see the conversation and video that started this topic, it's here
     
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  2. Danishblunt

    Danishblunt Notebook Virtuoso

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    by that logic all notebooks would die and having your PC on idle kills it.
     
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  3. don_svetlio

    don_svetlio Notebook Virtuoso

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    That wouldn't make much sense to me - reducing voltage usually results in lower thermals. What the VRMs do is take the +12V (or in this case I believe it's +15V) from the power supply and tone it down. Reducing the voltage applied to the CPU also reduces the required power since, IIRC, P=IxU. Sure, the VRMs aren't 100% efficient but their efficiency doesn't really depend on the CPU VID, does it?
     
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  4. THEBOSS619

    THEBOSS619 Notebook Geek

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    Exactly :D
     
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  5. Maleko48

    Maleko48 Notebook Evangelist

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    I think his main line of thinking is: lowering the voltage will cause the amperage to increase (which is even more closely related to heat than voltage).

    However, the supply voltage going to the VRMs themselves remains the same coming from the battery/mobo regardless of what output you are seeking. When we select that we want to undervolt the CPU more than stock, we are telling the VRMs they have to buck even more voltage (to ground?) than they were originally. I assume this causes additional heat and stress on the VRMs themselves but it's hard to say how much exactly.

    Does anyone know if the VRMs outputting the lower voltages are designed to maintain the same wattage output (this would cause amperage to go up, right?) Or if by lowering the voltage coming out of the VRMs the total overall power output in watts gets reduced and the current adheres to a preset curve?

    I think the main point to consider is whether operating your system at a lower total temperature across the board is more beneficial for the longevity of your system as a whole or if slightly reduced stress*** on a single component with higher overall system temps full time is the better way to go.

    I think lower temps across the board is the better way myself but that's just my $.02. I would love to hear from some electrical engineer types.

    Btw, is it the case that when undervolting, a CPU is more likely to run into current throttling issues due to needing a higher amperage limit in order to maintain the same maximum power output?
     
    Last edited: Apr 10, 2018
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