[HN Gopher] 12VO power standard appears to be gaining steam, wil...
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12VO power standard appears to be gaining steam, will reduce PC
cabling, costs
Author : CharlesW
Score : 52 points
Date : 2023-12-26 17:29 UTC (5 hours ago)
(HTM) web link (www.tomshardware.com)
(TXT) w3m dump (www.tomshardware.com)
| RedShift1 wrote:
| This seems dumb to me, it just moves parts of the power supply to
| the motherboard. Now if there's a power problem you have to
| replace the entire motherboard instead of just the power supply.
| In a couple of years you'll have an old motherboard with no new
| replacement options, if it fails you basically need a new
| computer because newer motherboards aren't compatible with your
| current CPU/RAM...
| teraflop wrote:
| Most of the motherboard's power consumption is dedicated to
| supplying the CPU, and that _already_ relies on the motherboard
| to step down from 12V to ~1V at a very high current. The
| demands on the 3.3V and 5V rails are pretty small in
| comparison.
|
| This change is unlikely to make motherboards significantly more
| failure-prone than they are now.
| elric wrote:
| > Components like RAMs, USB, and M.2 SSDs don't use 12v <snip>
| but 3.3V or 5V. The motherboard will be responsible for managing
| voltages for these components.
|
| Surely this will simply move part of the complexity from the PSU
| to the motherboard? Resulting in more efficient and simple PSUs,
| but more inefficient and complex motherboards? I've only ever had
| motherboards fail because of leaky capacitors or busted voltage
| regulators. The only PSU failure I've ever had was on account of
| a broken fan. Won't this lead to more motherboard failures?
|
| The cynic in me thinks that Intel would be fine with that,
| because that way they can sell more motherboard components.
| Gravityloss wrote:
| The motherboard can do the conversion next to where the low
| voltage is needed, reducing the distance and thus the amount of
| copper needed.
| photonbeam wrote:
| Half the mainboard is already just a PSU, this just means the
| big initial step down from 240v/120v is in a separate
| shielded/grounded box
|
| I somewhat wished they'd gone to 48vdc instead of 12vdc, though
| to further reduce cabling, but I guess that would be a big
| change, the 12vo seems much simpler
| eksu wrote:
| this is a computer not a car, 48v seems overkill and
| dangerous.
|
| components use 12v, 5v, or 3.3v in pcs currently. why do the
| step down from 48->12 instead of running 12v naturally? 12v
| is also what is used by the most power hungry components of a
| PC (GPU).
| dist-epoch wrote:
| The most power hungry component, the CPU, uses 1-1.5v.
|
| The GPU voltage is also step down to 1-1.5v by graphics
| cards VRMs.
| connicpu wrote:
| Power regulators that can efficiently produce the 1-1.5v
| output with the most minimal noise generally have lower
| maximums on their input voltage as well. In designing
| some of my own IoT devices I've looked into a fair number
| of power regulator ICs and 36V is a common maximum input
| voltage. The efficiency curves on the datasheets also
| usually show the efficiency gets lower the higher the
| input DC voltage. In a power regulator, inefficiency
| means even more heat you have to dissipate, not great in
| a GPU. I'm sure the GPU would love to take even lower
| voltage if it could, but 12V is the compromise we've
| decided on to get decent efficiency without requiring
| insanely thick conductors.
| photonbeam wrote:
| usbc can do 48v, its not that dangerous
| jauntywundrkind wrote:
| 48v seems vastly safer. There's 1/4 the thermal heating for
| equivalent power. The new high density 12VHPWR connector
| for GPUs has been melting down & had to get basically
| redesigned. That would not have been a problem at all on
| 48V.
|
| There shouldn't be an intermediary step down to 12V.
| Google's been doing direct step down from 48V->~1V with GaN
| fets for half a decade, which is vastly more power
| efficient than the two step 277V->12->1V that many server
| systems go through.
|
| It'd also be amazing to have usb-c extended power (48v) be
| something we could just add for free, essentially. (Alas
| this is complicated by needing to step down to lower
| voltages too, necessities some semiconductors in the
| delivery path to usb-c, which would have some voltage drop.
| This strongly implies to me something more like 52V or 54V
| would be ideal instead of 48V.)
|
| For anything that typically runs under 100W, I agree that
| 48V is ridiculous. But I would love love love to see some
| motherboards for ThreadRipper that have GaN fet for direct
| conversion from 48V, or stuff like that. It'd be pretty
| niche. But it should be an option!
|
| One of the big potential winners could be people with
| solar; being able to run your system directly off your
| solar bank would save double digits percent of power,
| versus inverting then converting back.
|
| You're right that in the immediate term we'd see a lot of
| intermediary conversions. I'd love to have a better game
| plan, for not just motherboards but other components to
| expect either 48v or wider voltage inputs. Non-trivial to
| support 10-60V but _if_ that was a market expectation &
| not a niche need we'd see _very_ affordable solutions
| spring up practically overnight. There 's already a range
| of usb-c focused power converters that are exceedingly
| cheap that could step in for this need!
|
| Edit: seems like Google is using two stage conversion
| primarily, but not necessarily 4:1 48V:12V. Their fixed
| ratio converter seems to have a 6:1 mode (8V) target as
| well, or be configurable for even bigger ratio (they said
| up to 12:1 in their talk). As of 2019, a bit of change of
| tune from original 2016 ambitions. Good talk?
| https://youtu.be/aBkz2JR4UVs
| cactacea wrote:
| 48V DC is completely safe and not dangerous whatsoever
| epcoa wrote:
| > 48v seems overkill and dangerous.
|
| In fact the exact opposite is true, it is safer in
| practice. In a true fault condition into flesh the currents
| involved aren't substantially less safe (4x microamps is
| still microamps). With protection circuitry and current
| limiting, the permitted currents are that much lower, which
| is easier to deal with.
| kyrra wrote:
| GN talked about this 8 months ago here:
| https://www.youtube.com/watch?v=Zc9oRKexV_s&t=4m15s
|
| That timestamp is where they address this issue. It seems the
| argument is that in sleep mode (low power modes), the system
| will draw overall less power with ATX12VO vs today's standards.
|
| Further, if you go directly to the specs:
| https://edc.intel.com/content/www/us/en/design/products-
| and-..., you can see they talk about ALPM (alternative low
| power mode) which seems to be the reasons for this design.
| toast0 wrote:
| A lot of the complexity already moved to motherboards. CPU and
| ram voltages are generated on the motherboard by necessity ---
| they don't run at 5v or 3.3v, they are adjustable in small
| steps based on load and configuration.
| gosub100 wrote:
| funny if we end up going full-circle back to replaceable VRMs
| like they had on dual CPU boards 25 years ago.
| Arnavion wrote:
| I'm not too worried about the complexity. What I *am* worried
| about is that your number of SATA power ports on your
| motherboard will become the limiting factor for how many SATA
| drives you can connect. The number of SATA *data* ports on the
| motherboard was not as much of a limiting factor because you
| can add data ports through M.2 / PCIe adapters.
|
| For example, the "MSI Pro H610M 12VO" hyperlinked in the
| article has a manual that shows it as having two SATA power
| ports, and an image shows one such port connecting to a single
| drive. Now I imagine this is a simplified illustration and
| maybe each port will have enough power to supply 3-to-4 HDDs
| (depending on current rating of the HDDs of course), but that's
| still a max of 8 HDDs. Meanwhile the non-12VO PSU I use has
| four ports available that can each connect to 3-to-4 HDDs each,
| so a max of 16 HDDs, and it definitely has enough spare power
| to support them because I sized the PSU for that need.
| marcosdumay wrote:
| Why not get a SATA PSU just like you are adding a dara
| adapter?
| Arnavion wrote:
| So two PSUs / power bricks? I'll just stick with non-12VO
| PSUs and boards as long as I can, and if enough people
| think like me then mobo manufacturers will continue
| stalling on 12VO.
| namibj wrote:
| No, an active converter from a PCIe power connector or
| such to SATA power. Perhaps integrated in many sata
| cards.
| doublespanner wrote:
| I suspect that you will have to get add in cards or drive
| caddies that also do power conversion, but these already
| exist (although expensive). More than 2-4 drives is starting
| to hit a point where you should start thinking about a
| different platform anyway.
| dwattttt wrote:
| In the post PATA days the available data connectors all map
| to disks 1:1, it knows how many power connectors would be
| needed for them. Expansion cards could probably supply power
| as well as data? I suppose other uses for those connectors
| would need to provide shims, much like the molex shims they
| use now.
| shadowpho wrote:
| Motherboard already manages a lot of low voltage regulators.
| The density and design of motherboard is much more suited to
| this then PSU
| bryanlarsen wrote:
| USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V. But
| those are all interface voltages, they're almost always stepped
| down on device to the actual voltage used.
|
| RAM doesn't have an interface voltage, it uses the voltage
| supplied, typically around 1.2V.
| Dylan16807 wrote:
| The vast majority of USB ports on a computer are using 5V.
|
| And M.2 using 3.3V is kind of weird and limiting.
|
| Though RAM does its own conversion now, starting with DDR5.
| duskwuff wrote:
| > USB uses 5V, 9V, 15V, 20V, 28V, 36V or 48V. M.2 uses 3.3V.
| But those are all interface voltages
|
| USB uses 3.3v signalling up through USBHS. (USBSS is 1V
| differential.) The higher voltages are for power delivery
| only.
| dist-epoch wrote:
| The problem with the current design is how to divide the power
| between the 12v, 5v and 3.3v rails.
|
| If you put most on 12v but you have a motherboard pulling more
| from 5v, you have a problem. Currently power supplies divide it
| based on average motherboard usage, but these slowly change,
| and your old power supply will stop having the optimum mix.
|
| The solution is to output it all on one rail.
| Arrath wrote:
| With the rapid uptick in power draw by CPUs and GPUs perhaps its
| time for ATX to go and an entirely new standard to come in[0],
| ditching the antiquated 12v rail and step up to 24 or 48v. We've
| got the twin kludges of the ever growing main power plug to the
| motherboard and the growth of supplemental power to the GPU first
| a 6-pin then 8, then two 6's etc etc and now with 12vhpwr and its
| attendant teething pains. When is enough enough?
|
| [0]Yes, cue the xkcd comic.
| Osiris wrote:
| Businesses seem to prefer incremental changes over large ones.
| Look at IPv4 vs IPv4. The two are completely incompatible and
| decades later we still haven't changed.
|
| 12v is a good compromise because PSUs can be manufactured to
| support both the new and old standard and motherboards could
| even accept ATX power inputs and just ignore the 5v and 3v
| rails.
|
| It allows for a transition period that's much smoother than a
| complete revamp. It's the more pragmatic solution.
| Dalewyn wrote:
| >Look at IPv4 vs IPv4.
|
| I'm not sure if this was a typo or deliberate, but either way
| the irony is beautiful.
|
| >12v is a good compromise because PSUs can be manufactured to
| support both the new and old standard and motherboards could
| even accept ATX power inputs and just ignore the 5v and 3v
| rails.
|
| The biggest sticking point with 12VO is that it's physically
| incompatible with ATX. 12VO doesn't provide the voltages ATX
| expects (obviously), nor does 12VO provide compatible
| physical connections (this incompatibility is a selling
| point).
|
| ATX's biggest selling point and why we still use it to this
| day is its backwards and forwards compatibility. Outside of
| certain outliers you can just expect an ATX PSU to work with
| ATX equipment, regardless of when you buy or bought the
| parts; the virtues of a well-followed industry standard.
| intrasight wrote:
| Standards must evolve
| aftbit wrote:
| I agree with your larger point. That said, here in 2023 in
| the US, my phone only gets an IPv6 address from its LTE
| network. Of course there's some NAT6to4 somewhere that makes
| this all transparent to me, and I can still access v4-only
| resources just fine.
| shadowpho wrote:
| 24v requires more cost.
| 0xcde4c3db wrote:
| While we're dreaming, could we also replace M.2 slots on
| desktop boards with U.2 or OCuLink connectors? M.2 is optimized
| for thin, light portable devices like laptops and tablets; it
| makes zero sense in a desktop, where it basically just wastes
| board space and makes cooling more awkward.
| kloch wrote:
| What is old is new again:
|
| https://en.wikipedia.org/wiki/S-100_bus
|
| > Power supplied on the bus is bulk unregulated +8 Volt DC and
| +-16 Volt DC, designed to be regulated on the cards to +5 V (used
| by TTL ICs), -5 V and +12 V for Intel 8080 CPU IC, +-12 V RS-232
| line driver ICs, +12 V for disk drive motors. The onboard voltage
| regulation is typically performed by devices of the 78xx family
| (for example, a 7805 device to produce +5 volts). These were
| linear regulators which are commonly mounted on heat sinks.
| Dylan16807 wrote:
| Both kinds of power supply have existed simultaneously and in
| wide use for a long time. Neither design is "old". We're not
| going "back".
| nimish wrote:
| 48V now! It's already there in the server space and automotive
| space. Would drastically reduce cabling size and complexity.
|
| Efficiency jumps a little too. 48V to PoL is pretty common now as
| well.
| sowbug wrote:
| As I understand it, 48V makes sense for the long cable runs of
| PoE and server racks, as well as the varying voltage needs of
| cars. But a PC doesn't have such runs, and 12V is already
| higher than any PC component's voltage. It seems like a good
| tradeoff.
| samtho wrote:
| This is correct. I see a future where there is an optional
| 48VDC line that is run in our homes to power stuff like LED
| lights and dedicated USB ports. This can become especially
| important for homes that use solar and stored electricity
| where you might be having to go from 48VDC -> 120/240VAC ->
| 12VDC -> 5VDC (see note) with each conversion resulting in
| the loss of some power due to the fact that these cannot be
| 100% efficient.
|
| Note: a lot of flyback-style transformers are setup to step
| down the AC voltage 1/10th (12V in 120VAC, 24V in 240VAC)
| because transformers are cheap/abundant for that. It's
| cheaper often to put a buck converter that takes any voltage
| from 12-24V and convert it to a fixed required voltage.
| newZWhoDis wrote:
| If we're moving to a new standard I'd much rather we
| standardize around 240V DC with an improved plug design.
|
| You'd have HUGE savings on the copper required for a
| standard home, plus you'd get a substantial increase in
| power capacity.
| xxs wrote:
| 240VDC conversion to any low voltage (1V for cpu/gpu)
| won't happen.
|
| Most of the copper is spent on carrying hundreds of amps
| at low voltage not the 12V lanes.
| calamari4065 wrote:
| 240VDC is way too dangerous for residential use. And
| really it's not super practical to drop that down to 5v
| for charging your widgets. 48V makes much more sense.
|
| And for that matter, I wouldn't want 240VDC on utility
| poles either. If a line goes down, it's so much more
| dangerous.
|
| The more sane solution would be a high capacity DC
| converter installed next to the line transformer that
| feeds your street. DC infrastructure _inside_ the home
| makes total sense at moderate voltages. City scale DC at
| line voltages is honestly terrifying.
| rini17 wrote:
| Why not just throw in a DC/DC converter from 48 to 12V? You
| need protection anyway (so that failure won't take down
| your whole 48V microgrid) and perhaps even management.
| CamperBob2 wrote:
| No, 12V is already too low for the most power-hungry PC
| components (GPUs), as witnessed by the trouble nVidia has had
| with power connectors on the 4090.
|
| If they're going to go to the trouble of coming up with a new
| standard, it's asinine to base it on 12 volts, which is
| already known not to be sufficient. They need to use 48V.
| xxs wrote:
| The GPU runs at 1V (sub 1V usually). The issues with the
| power delivery and the nvidia connector are their own.
| CamperBob2 wrote:
| That's not how it works. The GPU receives power at 12V
| via the PCIe 8/6+2 connector at 20-30 amps or so. It then
| steps that down to ~1 volt at the point of load, at
| hundreds of amps, but that's irrelevant.
|
| The problem is that safely handling "20-30 amps or so"
| cannot really be done with cheap consumer-level Molex
| connectors, or at least should not be done, ideally. More
| expensive connectors are needed, so what they are doing
| now is asking for trouble. However, the voltage doesn't
| determine how hot it gets; only the current influences
| that. If they were distributing power at 48 volts, the
| current would be about 1/4 what it is now, and
| overheating at the connector would not be an issue.
| xxs wrote:
| says 600W GPU, that's 50A. Screw based connectors would
| do just fine - delivery 48V would require to step it down
| to some other (sub 20) voltage first. That part would be
| at the GPUs.
|
| Also I do understand how it works.
| CamperBob2 wrote:
| Yes, certainly, using better connectors would head off
| overheating problems. That's not free. Something else
| that isn't free is extra copper in the wire harnesses
| from the PSU.
|
| Meanwhile, it's true that point-of-load regulation from
| 48V directly to 1V will be less efficient (well, maybe;
| see nimish's link below). But by the same token,
| regulation in the PSU would be more efficient if it
| didn't have to go all the way down from 150-300 VDC on
| the primary side down to 12 at the output.
|
| A good compromise would probably be the geometric mean
| between a few hundred volts and the voltage at the load
| with the highest current. Assuming 250 volts on the
| primary as a compromise between 120/240VAC operation and
| 1V all the way downstream, that would be about 16 volts.
| Doesn't seem like a big improvement, but it would be
| enough to lower the current at the GPU input connector by
| about 1.8x compared to 12 volts.
|
| Either way, sticking with 12 volts in any new standard is
| just stupid. 48 has another advantage, which is that
| automotive is going to (finally) start moving to it over
| the next few years. There could be a lot of room for
| parts-sharing between the two industries.
| fbdab103 wrote:
| I was disappointed they did not make the jump to 19V, which is
| standard in laptops. A far less drastic change which is already
| handled by component manufacturers.
| xxs wrote:
| 48V -> 1V (for the cpu) would be super extra funny, though. The
| power stages would need to be high voltage mosfets. No idea if
| a single conversion 48 ->1V at 400A+ would make any sense.
|
| Also the capacitive coupling for 48v is quite more dangerous.
| nimish wrote:
| https://www.princeton.edu/~minjie/files/jaeil_apec20_paper.p.
| .. People are waaaay ahead of you. The 48V -> 12V -> ~1V is
| apparently less efficient than a 48V -> 1V even with the
| really high step down ratio.
| hoosieree wrote:
| DC has zero capacitive (or inductive) coupling.
| Dylan16807 wrote:
| That needs a two stage converter down to chip voltages, doesn't
| it?
|
| It's a reduction in cables, but I wouldn't say _drastic_. An
| 8-pin with good components can handle over 500 watts at 12
| volts. Just modernizing gives you most of the possible benefit.
| lazide wrote:
| Eh, 500 watts at 12 volts is 42 amps. Assuming half of those
| 8 pins are positive, the other negative thats 10 amps per
| pin.
|
| You'd better not have any corrosion in that connector, or a
| loose wire if you want to be able to do that without fire
| risk. And you'll get non-trivial resistive heating in many
| cases over time.
|
| Doing the same at 48 volts is 10.5 amps total, 2.6 amps per
| pin. Hard to mess that up.
| hex4def6 wrote:
| If you're designing a new power delivery method from scratch, I
| wonder if 12V is the right voltage.
|
| It seems you could take a page out of the laptop handbook and go
| to USB-C 20V standard. There must already be a whole ecosystem of
| 20V capable PMICs / SMPS already, so this doesn't seem like it
| would be a drastic change.
|
| Heck, it seems like we should just jump to the USB C power
| delivery standard for desktop PCs. The high end is currently 48V
| / 240W (which I'm guessing is a limitation of the connector + max
| safe voltage). Either go with a different design for the
| connector to get above 240W, or just parallel up 2-4x USB C
| connectors internally. That would be more than sufficient.
|
| I'm sure you'd be taking advantage of some of the production
| scale of laptops.
|
| And this would allow easy extension to stuff like power external
| monitors etc from the desktop PC directly. Being able to charge a
| laptop and have an external display (or two) all connected to the
| desktop PC instead of their own dedicated power bricks would be
| awesome.
| geocrasher wrote:
| This is a far cry from the AT days when you could swap the
| motherboard power connectors and let all the magic smoke out.
| Those were the days. I never did it myself, but I watched a guy
| who was doing a working interview for a job (to be fair I was
| doing the same!) smoke a computer that way during his interview.
| They hired him anyway, and they also hired me. It ended up being
| the worst job I'd had to date. I don't miss the crappy computer
| shops of the late 90's. The good ones though, those were gold.
| spuz wrote:
| I'd love to see some 12VO mini-itx boards and SFX or flex PSUs.
| The most challenging thing when it comes to building a small form
| factor PC is routing the ATX power cable and that connector is so
| stiff god forbid you ever need to disconnect it to do some
| maintenance. Small form factor PCs have benefited a lot since the
| move away from IDE drives but things could still be significantly
| improved to get more power into a small space.
| pants2 wrote:
| It pains me that in my home server setup, I have solar panels
| that produce DC, then an inverter converts that to AC for the
| wall outlet, then my UPS converts that to DC to charge its
| battery, which converts it back to AC to plug my servers into,
| then the server PSU converts it to DC to power the components.
| All that switching has to waste a lot of energy
| (DC->AC->DC->AC->DC).
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