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How safe is it to power GPU from a separate Power Supply can one turn the GPU Power supply main switch On or Off as required ?

How safe is it to power GPU from a separate Power Supply ? Can one turn the GPU Power supply Main switch On or Off as required ?
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More about safe power gpu separate power supply turn gpu power supply main switch required
  1. you could do it i saw it with laptops with external gpus so its definately possible and safe you could turn the gpu power supply off just like your main power supply when your computer is off (turning it off while the computer is on would cause black screen and could damage the gpu)
  2. Why not just get a PSU of proper size to run the GPU and the rest of the system.

    As for the above, a laptop with an eGPU is a whole different thing.
    And seeing it on a youtube video didn't show you the following explosion when you find out it was wired incorrectly.
  3. ^^ ill just take the power supply experts word on this xP
  4. It's definitely possible, but for almost the same money, you could get a 600W PSU to power all of your system.
    Finding a good PSU under $50 is almost impossible anyway. $50 is what a 620W Seasonic S12II costs, a very good PSU.
    ------------------------------------------------------------------------------------------------------------
    Wiring isn't all that difficult, there is a wire in the ATX(green) connector that starts the PSU, that wire is then connected with a black wire(ground).
    It's connected by taking a new wire, and putting one end in the green wire pin and the other end in the black wire pin.
    From here, you can add a switch in the middle of the new wire, to connect or disconnect the two halves.
    As for connections to the GPU, it's the same as always, connect the 6/8 pin to the GPU.

    I don't recommend this over the first method, I would only do this, if I had a spare PSU laying around and really don't have any cash around for a new one.
  5. not you said:
    you could do it i saw it with laptops with external gpus so its definately possible and safe you could turn the gpu power supply off just like your main power supply when your computer is off (turning it off while the computer is on would cause black screen and could damage the gpu)


    Thank you for the response.

    Can one switch between Intel GPU and dedicated GPU, in desktop ?

    If the monitor in use both Intel and dedicated GPU connected -- and if using Intel GPU alone, can one disable the dedicated GPU through device manager ( maybe BIOS also ) and turn Off the dedicated GPU's separate Power Supply ?

    Please tell why it can damage the GPU.
  6. You cannot turn off your GPU while in Windows, you have to do it in BIOS.
  7. lakimens said:
    It's definitely possible, but for almost the same money, you could get a 600W PSU to power all of your system.
    Finding a good PSU under $50 is almost impossible anyway. $50 is what a 620W Seasonic S12II costs, a very good PSU.
    ------------------------------------------------------------------------------------------------------------
    Wiring isn't all that difficult, there is a wire in the ATX(green) connector that starts the PSU, that wire is then connected with a black wire(ground).
    It's connected by taking a new wire, and putting one end in the green wire pin and the other end in the black wire pin.
    From here, you can add a switch in the middle of the new wire, to connect or disconnect the two halves.
    As for connections to the GPU, it's the same as always, connect the 6/8 pin to the GPU.

    I don't recommend this over the first method, I would only do this, if I had a spare PSU laying around and really don't have any cash around for a new one.


    Thank you for the response.

    Please expand further on why connecting the green and black wire is necessary before using a spare power supply with the dedicated GPU.

    Can one not independently power the dedicated GPU power supply - that is switching the second power supply through the wall socket --- or do both motherboard as well as dedicated GPU power supply need to be in sync ?
  8. lakimens said:
    You cannot turn off your GPU while in Windows, you have to do it in BIOS.


    Does a desktop motherboard BIOS have option to switch between the Intel GPU and dedicated GPU ? If yes, can one after enabling the Intel GPU, switch of the dedicated GPU power supply ? Is it safe ?
  9. USAFRet said:
    Why not just get a PSU of proper size to run the GPU and the rest of the system.

    As for the above, a laptop with an eGPU is a whole different thing.
    And seeing it on a youtube video didn't show you the following explosion when you find out it was wired incorrectly.


    Thank for the response. What difference are you referring to ? Please elaborate.
  10. Hi,
    Basically, if you have to ASK how to do this you probably should NOT.

    You are asking about WIRING questions, and frankly I and many others are not comfortable pointing you down that road. Heck, I have an electronics degree and personally would NOT do this unless it was some weird project.

    *Buy a proper PSU with the correct number of PCIe 6/8-pin cables or provide your CPU, GPU, and current PSU models so we might give better advice.

    Your current PSU may even be capable with an adapter (i.e MOLEX-> 6-pin).
  11. Is switching between Intel GPU and dedicated GPU possible with a desktop ?

    If yes, wouldn't turning off the separate power supply connected to the dedicated GPU while it is disable in BIOS, save power usage.
  12. photonboy said:
    Hi,
    Basically, if you have to ASK how to do this you probably should NOT.

    You are asking about WIRING questions, and frankly I and many others are not comfortable pointing you down that road. Heck, I have an electronics degree and personally would NOT do this unless it was some weird project.

    *Buy a proper PSU with the correct number of PCIe 6/8-pin cables or provide your CPU, GPU, and current PSU models so we might give better advice.

    Your current PSU may even be capable with an adapter (i.e MOLEX-> 6-pin).


    If the main PSU has limited wattage, can one use a spare PSU for the dedicated GPU and wouldn't turning it Off ( after disabling it in BIOS and switching to Intel GPU, with a monitor that has two output ports ) save power

    Please elaborate on why connecting the green and black wire is necessary before using a spare power supply with the dedicated GPU.

    Can one power the second power the second power supply independently or is it required to sync the two power
    supplies ?
  13. Connecting the green and black wire is necessary to turn on the second PSU, because usually it's the motherboard that does this for you, in this case there is no motherboard, so you have to do it manually.

    Answer to first question: If you're asking if you should turn it off if the GPU is not in use, then yes, that's how it should be.

    You should do a lot of research if you do this. Google for people that have already done it.
  14. This seems to be a quest of power saving for the electricity bill. Correct?
    No.

    If the system is at a usage level where you can just use the iGPU, then running the regular GPU is ALSO of little power usage.
    The GPU does not run at full power all the time.

    The PSU only delivers what the system is requesting.
    And a better quality, somewhat higher power PSU is probably more efficient than trying to run 2 low power ones.

    My main system (specs under my avatar) consumes 81 watts at idle.
    CPU, GPU, drives, everything.
    At idle, running 24/7, that is approx $7.10/month.

    So lets turn off that GPU.
    Turning off the GPU might reduce that by..5 watts? 10 watts?
    I'm not going to dismantle the system to test this, but let's assume 10 watt difference.
    Ooooo....that saves $0.80 month. 80 cents.

    If you're looking to conserve energy usage in the house, the PC is far down the list of things to do.
  15. lakimens said:
    Connecting the green and black wire is necessary to turn on the second PSU, because usually it's the motherboard that does this for you, in this case there is no motherboard, so you have to do it manually.

    Answer to first question: If you're asking if you should turn it off if the GPU is not in use, then yes, that's how it should be.

    You should do a lot of research if you do this. Google for people that have already done it.


    Thank you for the resonse

    Does BIOS really allow switching between Intel GPU and dedicated GPU before booting into Windows ( that has drivers for both ) ?

    If yes, would turning off the dedicated GPU power supply at the wall outlet ( after first disabling in BIOS ) - turn off the dedicated GPU ? Would switched off separate power supply power off the dedicated GPU, considering it is still connected to the PCIe slot ?
  16. USAFRet said:
    This seems to be a quest of power saving for the electricity bill. Correct?
    No.

    If the system is at a usage level where you can just use the iGPU, then running the regular GPU is ALSO of little power usage.
    The GPU does not run at full power all the time.

    The PSU only delivers what the system is requesting.
    And a better quality, somewhat higher power PSU is probably more efficient than trying to run 2 low power ones.

    My main system (specs under my avatar) consumes 81 watts at idle.
    CPU, GPU, drives, everything.
    At idle, running 24/7, that is approx $7.10/month.

    So lets turn off that GPU.
    Turning off the GPU might reduce that by..5 watts? 10 watts?
    I'm not going to dismantle the system to test this, but let's assume 10 watt difference.
    Ooooo....that saves $0.80 month. 80 cents.

    If you're looking to conserve energy usage in the house, the PC is far down the list of things to do.


    Thank you for the response

    So do you imply - when not required one can disable the dedicated GPU and then later, switch off its power supply at wall outlet ? So does motherboard BIOS allow manual switching between Intel and dedicated GPU ?

    The reason we were asking if one could turn off the dedicated GPU power supply when not required in tasks Intel GPU can handle - is because we were of the opinion that for those same tasks a dedicated GPU uses more power. It has more components integrated to run power through, to keep it switched on. Or does it use just the same amount of power compared to Intel GPU ?
  17. In a state where using the integrated GPU would be OK...the dedicated GPU would also be at a low power usage state.

    Before building such a weird and potentially hazardous configuration, it would be helpful to know if what you propose has any actual effect.

    Run the system from the iGPU, in tasks where that will work.
    How much power does the entire system consume?

    Now, run the system with the actual GPU running, doing those same tasks.
    How much power does the entire system consume?

    What is the actual wattage difference?
    5 watts? 10? 50?
    Find that number, and then do the math for the energy saving $$ from your power company.
    If it is more than $2/month, I'll be surprised.

    You can't just assume it will be better/cheaper...actual evidence is the key here.
    You must know.
  18. Then (and this is impossible to test unless you actually build it)...what is the overall power draw if you had 2 power supplies running?
    One to power the system, and one to power the GPU when you need to actually run the GPU.
    It may be more than just a single good quality power supply, running the whole thing all the time.

    Your overall power usage may be more, trying to run 2x PSUs, and switching things back and forth.
  19. USAFRet said:
    Then (and this is impossible to test unless you actually build it)...what is the overall power draw if you had 2 power supplies running?
    One to power the system, and one to power the GPU when you need to actually run the GPU.
    It may be more than just a single good quality power supply, running the whole thing all the time.

    Your overall power usage may be more, trying to run 2x PSUs, and switching things back and forth.


    If the main PSU has limited wattage, can one use a spare PSU for the dedicated GPU and would turning it Off ( after disabling it in BIOS and switching to Intel GPU, with a monitor that has two output ports ) save power ?

    Would it be electrically safe ?

    Is enabling Intel GPU in BIOS even possible, when the dedicated GPU is installed in the BIOS possible ?

    We wish to know if something like NVIDIA OPTIMUS is possible in desktop.

    There is no high wattage DC to DC PSU. The maximum wattage for a DC to DC PSU is 500W. Many over-clocked GPU have a wattage spikes of upto 350W.
  20. Best answer
    I don't think you are grasping the hassle of what you're trying to accomplish for very little financial benefit.

    You would NOT be switching constantly between graphics. You would run the dedicated graphics card by itself, and as said above somewhere it will go into a low power state.

    My GTX1080 uses 7W (seven Watts) only in complete idle. Probably closer to 30W when browsing (depends on a few factors).

    If you were buying an expensive video card, then just buy the proper PSU since the cost will be small relative to the high-end GPU cost.

    Conversely, if buying a relatively inexpensive video card you can buy a cheap PSU ($35+ USD or so) that works there though a 300W PSU might be suitable for some systems even with a GTX1050Ti.

    You do NOT want to be hooking up a separate power supply. Now you have to do some wiring. It's outside the case. All for what? At best you save the cost of a new PSU.
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