• Old PSU

    From Jeff Gaines@21:1/5 to All on Sat May 11 12:39:16 2024
    As art of my clean up I have found a Corsair case with a PSU that has just
    two cables coming out, one with the big (?24 pin) connector and the other
    with two of the small square connectors.

    Memory is struggling but is that from the days when we fed power just to
    the motherboard and then plugged peripherals into the board? If so it's probably for the bin?

    --
    Jeff Gaines Dorset UK
    If you ever find something you like buy a lifetime supply because they
    will stop making it

    --- SoupGate-Win32 v1.05
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  • From Andy Burns@21:1/5 to Jeff Gaines on Sat May 11 14:30:02 2024
    Jeff Gaines wrote:

    As art of my clean up I have found a Corsair case with a PSU that has
    just two cables coming out, one with the big (?24 pin) connector and the other with two of the small square connectors.

    sounds like ATX12V P4 connector to the CPU(s)

    Memory is struggling but is that from the days when we fed power just to
    the motherboard and then plugged peripherals into the board? If so it's probably for the bin?

    Sure you've not "harvested" the cables with 3.3/5/12 volts to drives? Or
    it's a modular PSU with cables removed?

    There is a new(ish) standard called 12VO, where the PSU feeds 12 to the motherboard, which then feeds lower voltage(s) to the peripherals.

    --- SoupGate-Win32 v1.05
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  • From Daniel James@21:1/5 to Andy Burns on Sat May 11 15:11:56 2024
    On 11/05/2024 14:30, Andy Burns wrote:
    There is a new(ish) standard called 12VO, where the PSU feeds 12 to the motherboard, which then feeds lower voltage(s) to the peripherals.

    Am I alone in thinking that's a pretty stupid "standard"?

    Firstly, the motherboard has to provide the conversion to 5V and 3.3V
    that would previously have been done by the PSU, so the cost of a board
    will go up -- and you can bet that a 12VO PSU won't be significantly
    cheaper than an ATX one so there'll be no saving thare. This means that
    if the voltage-shifting functionality fails it will mean a new
    motherboard (which will probably mean changing CPU, RAM, etc. unless the
    board fails when it's new enough for a like-for-like replacement) not
    just a new PSU.

    Secondly, the motherboard will have to handle the current needed for
    drives, etc., that are now fed directly from the PSU, which means
    heavier tracks and possibly more heat generated on the board.

    It also means that one has to worry about the current that a motherboard
    is able to handle -- and the number of power output connections provided
    -- if designing a system that is to have, say, an unusually large number
    of drives.

    I can't see any upside, for the user. I hope 12VO vanishes without trace!

    --
    Cheers,
    Daniel.

    --- SoupGate-Win32 v1.05
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  • From Jeff Gaines@21:1/5 to All on Sat May 11 14:14:01 2024
    On 11/05/2024 in message <la9a72F9di4U5@mid.individual.net> Andy Burns
    wrote:

    Jeff Gaines wrote:

    As art of my clean up I have found a Corsair case with a PSU that has
    just two cables coming out, one with the big (?24 pin) connector and the >>other with two of the small square connectors.

    sounds like ATX12V P4 connector to the CPU(s)

    Memory is struggling but is that from the days when we fed power just to >>the motherboard and then plugged peripherals into the board? If so it's >>probably for the bin?

    Sure you've not "harvested" the cables with 3.3/5/12 volts to drives? Or
    it's a modular PSU with cables removed?

    There is a new(ish) standard called 12VO, where the PSU feeds 12 to the >motherboard, which then feeds lower voltage(s) to the peripherals.

    Thanks for making me look again, you are right, I couldn't see the sockets
    in the gloomy spare room without a torch!

    Thanks again :-)

    --
    Jeff Gaines Dorset UK
    Tell me what you need, and I'll tell you how to get along without it.

    --- SoupGate-Win32 v1.05
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  • From Theo@21:1/5 to Daniel James on Sat May 11 16:09:30 2024
    Daniel James <daniel@me.invalid> wrote:
    On 11/05/2024 14:30, Andy Burns wrote:
    There is a new(ish) standard called 12VO, where the PSU feeds 12 to the motherboard, which then feeds lower voltage(s) to the peripherals.

    Dell, Lenovo and friends have long done that for their desktops.

    Am I alone in thinking that's a pretty stupid "standard"?

    Firstly, the motherboard has to provide the conversion to 5V and 3.3V
    that would previously have been done by the PSU, so the cost of a board
    will go up -- and you can bet that a 12VO PSU won't be significantly
    cheaper than an ATX one so there'll be no saving thare. This means that
    if the voltage-shifting functionality fails it will mean a new
    motherboard (which will probably mean changing CPU, RAM, etc. unless the board fails when it's new enough for a like-for-like replacement) not
    just a new PSU.

    Secondly, the motherboard will have to handle the current needed for
    drives, etc., that are now fed directly from the PSU, which means
    heavier tracks and possibly more heat generated on the board.

    It also means that one has to worry about the current that a motherboard
    is able to handle -- and the number of power output connections provided
    -- if designing a system that is to have, say, an unusually large number
    of drives.

    I can't see any upside, for the user. I hope 12VO vanishes without trace!

    It's about having a lower cost system. Peripherals are increasingly onboard these days - think M.2 SSDs where we once had SATA. As well as reducing in number, the current demand of off-board loads is much lower (SSD v HDD).
    The days when normal users would stuff half a dozen HDD, a DVD and a tape
    drive in their office desktop are gone - that's what they use NASes, servers and the cloud for these days.

    Basically having a PSU pump out 5V at 20A and then use it for a single 2W
    SSD is wasteful, so move that conversion to the mobo where you can size the converters for the loads your system actually expects to have. That also
    makes the conversion more efficient. Maybe you only need 10W so you have a much smaller converter.

    The remaining use case for high power systems is 'enthusiasts', who won't
    buy an office PC from Dell anyway, or people with big GPUs. In which case
    they need to swap out the in-box 200W PSU for a 600W monster anyway.

    Servers have done this for decades: big iron might have a 2.4kW PSU that
    only outputs 12V, and the rest is either on the mobo, backplanes or in a separate converter board. That's enough to power their 4 CPU sockets and 24 drive bays or whatever they have.

    Theo

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  • From Daniel James@21:1/5 to Theo on Sun May 12 11:58:39 2024
    On 11/05/2024 16:09, Theo wrote:
    On 11/05/2024 14:30, Andy Burns wrote:
    There is a new(ish) standard called 12VO, where the PSU feeds 12
    to the motherboard, which then feeds lower voltage(s) to the
    peripherals.

    Dell, Lenovo and friends have long done that for their desktops.

    Really? It's been a while since I had occasion to poke around inside a
    recent one of those.

    I can't see any upside, for the user. I hope 12VO vanishes without
    trace!

    It's about having a lower cost system.

    Yes, lower cost to manufacture at the cost of versatility for the user.

    I suppose I should applaud the potential saving in materials as these
    designs don't have to cater for situations that usually won't arise, but
    I hate this "vanilla-ization" of commodity systems.

    Peripherals are increasingly onboard these days - think M.2 SSDs
    where we once had SATA.

    I hate M.2. I like my drives in caddies so they can be swapped around
    without opening the case, and M.2 doesn't allow for that. Well, you can
    use M.2 disks in USB caddies, but that's a compromise. Might as well use
    SATA.

    The days when normal users would stuff half a dozen HDD, a DVD and a
    tape drive in their office desktop are gone - that's what they use
    NASes, servers and the cloud for these days.
    I don't think "normal" users ever stuffed half a dozen HDDs into a
    desktop PC. The most I've ever had was two, and that was when disks were
    a bit smaller than they are today and you needed more than one. As you
    say that's a job for a NAS/Server.

    Basically having a PSU pump out 5V at 20A and then use it for a
    single 2W SSD is wasteful, so move that conversion to the mobo where
    you can size the converters for the loads your system actually
    expects to have. That also makes the conversion more efficient.
    Maybe you only need 10W so you have a much smaller converter.
    Yes, I see that point ... but surely that's an argument for encouraging
    people to pick a PSU that has the right power available at each voltage
    -- and, indeed, an argument for not fitting a ridiculously
    over-specified PSU, as so many people seem to do.

    Putting the PSU functions on the mobo limits the usefulness of the whole system, so the mobo (and probably everything else) needs to be replaced
    just to increase the power availability.

    I can see that for an off-the-shelf corporate PC that will be sold in a particular configuration and only ever used in that configuration there
    is no need for flexibility and the 12VO scheme may reduce manufacturing
    costs ... but as soon as you start to talk about a system that may need
    to be upgraded or used in different ways you're either looking at
    replacing the mobo to get more power-handling or you're looking at
    starting with an over-spec'd mobo that will be able to handle the
    upgrades -- either of which will wipe out that initial costs saving.
    Much cheaper to replace a PSU!

    The remaining use case for high power systems is 'enthusiasts', who
    won't buy an office PC from Dell anyway, or people with big GPUs. In
    which case they need to swap out the in-box 200W PSU for a 600W
    monster anyway.

    In this newsgroup its the enthusiasts I have in mind, of course.

    I suppose what I'm really saying is that I hope the advent of 12VO and
    the likes doesn't spell the end of normal ATX-type PSUs for those of us
    that want them.

    Servers have done this for decades: big iron might have a 2.4kW PSU
    that only outputs 12V, and the rest is either on the mobo, backplanes
    or in a separate converter board.

    I've no issue with server systems using the backplane or specialist
    converter boards to manage the power -- that's sensible -- but also very different from making the mobo do it!

    --
    Cheers,
    Daniel.

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  • From Andy Burns@21:1/5 to Daniel James on Sun May 12 13:50:57 2024
    Daniel James wrote:

    I hate M.2. I like my drives in caddies so they can be swapped around
    without opening the case

    More what U.2 was designed for, than M.2 ...

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