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Intel is changing the future of power supplies with its ATX12VO spec

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Re: Intel is changing the future of power supplies with its ATX12VO spec

#131

Post by jaclaz »

Only as anecdata, in my practical experience over the years, I needed to change many power supplies[1], and very few motherboards. (excluding replacements due to upgrades)

I would go a little bit further and say that the PSU is probably the most replaced "standard" part of a PC, followed by hard disks.

I also a couple times repaired a PSU replacing this or that failed component, but it is simply not worth the time and money, as spare new PSU's are cheap enough, the replacing is very easy whilst even procuring a single chip or capacitor is complex for non-professionals, besides the soldering tools, etc.

Hopefully the parts that age or however tend to fail will remain in the (easily replaceable) PSU, otherwise we will see an increase in replaced motherboards.

Some sort of (standard) "daughterboard" with the voltage regulating components would have made more sense (to me), but surely it makes less sense from an industrial manudacturing point of view.

[1] be it due to capacitors, power transistors or mosfets or whatever, and due to whatever reasons, be it aging, power surges, etc.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#132

Post by simias »

russdill wrote: post #126

In one sense this feels like pushing the efficiency problem under the rug. There's a requirement for power supplies to meet a certain efficiency standard, and generating 3.3v and 5v rails are pushing that number down. Solution? Move that task to the motherboard where they won't count against the power supply efficiency requirement. Of course, from a purely engineering perspective, it really does make sense and it's o…

The motherboard "knows more" than the PSU though, it should be able to better deal with these idle power situations by shutting down things that aren't used anymore and powering them back up when needed. An external PSU would have tighter constraints regarding power availability and wouldn't be able to optimize the power profile quite as aggressively since they don't really know exactly what they're driving.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#133

Post by close04 »

jdietrich wrote: post #73
DiabloD3 wrote: post #27

Four important things to consider: First, this already happened to some extent. Outside of drives and fans, the virtually all of the power used in your system is exclusively 12v; either from the 12v pins on your ATX24 or P4 or EPS12 connectors, or via the PCI-E connectors; very little non-drive or non-fan power is supplied via 3.3 or 5v rails. Second, almost all PSUs today use 12v DC to 3.3/5v DC converters to increa…

>First, this already happened to some extent. Fujitsu have been building PCs for a number of years with proprietary 12v-only PSUs, with SATA power being provided from an auxiliary connector on the motherboard.

Basically every OEM small PC (everything below SFF from Lenovo, HP, Dell, Fujitsu, etc. which do not accept PCIe extension cards and are pretty much built from laptop parts) is now powered from laptop brick PSUs. Which means everything inside the desktop is derived off of a single 19-20V DC line. SFFs still use internal PSU but they're all custom and while I haven't opened up one recently I'm sure they dropped as many of the rails as possible since they have full control of the MoBo/PSU design. The only PCs that use ATX PSUs are full towers in general.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#134

Post by cesarb »

thehobgoblin wrote: post #129
numpad0 wrote: post #98

Earlier quoted context omitted.

Why is it 19V for laptops? I had suspected it’s to compensate for voltage drop at linear regulators. Batteries are either 11.1(3.7v 4 cells) or 14.8(3.7v 3 cells 1-3 parallel) and these voltages doesn’t seem immediately consistent with ATX12V to me.

The nominal voltage of a battery isn't the maximum voltage, 3.7V lithium cells are typically charged to around 4.2V. A 4S battery (or equivalent) will have a nominal voltage of 14.8V and a maximum voltage of 16.8V, which leaves 2.2V extra, probably to account for losses. Why 19V ended up being the typical voltage rather than rounding it up to something like 20V or 24V is beyond me (probably a matter of compliance, tr…

I have seen many laptops where the charger sticker says the output voltage is 19.5V. And the nearest USB-C standard voltage is 20V, so that's probably what most newer laptops which charge through a USB-C socket use.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#135

Post by Faaak »

russdill wrote: post #126

In one sense this feels like pushing the efficiency problem under the rug. There's a requirement for power supplies to meet a certain efficiency standard, and generating 3.3v and 5v rails are pushing that number down. Solution? Move that task to the motherboard where they won't count against the power supply efficiency requirement. Of course, from a purely engineering perspective, it really does make sense and it's o…

Exactly. I'm pretty sure that once the DC-DC converters are mainly placed in the motherboard, they won't be audited for efficiency anymore and global efficiency will plummet.

A shame

Re: Intel is changing the future of power supplies with its ATX12VO spec

#136

Post by effie »

PaulDavisThe1st wrote: post #63

I love computers with 12VDC native power jacks. Why? My solar-powered van (interior only, the engine is still diesel) is 12VDC everywhere, and that's good clean battery DC, not some noisy-ass AC/DC conversion. I love it so much that 2 of the last 3 computers I built (on an ATX form factor) were 12VDC native. I have external AC/DC power supplies for them, but when travelling/living in a solar-powered environment, I ge…

> I built (on an ATX form factor) were 12VDC native

I want this! Mainly to run from batteries efficiently, transforming from DC to AC and then back to DC is so absurd. Can you give any photos/links/recommendations on how to start?

Re: Intel is changing the future of power supplies with its ATX12VO spec

#137

Post by unlinked_dll »

jaclaz wrote: post #131

Only as anecdata, in my practical experience over the years, I needed to change many power supplies[1], and very few motherboards. (excluding replacements due to upgrades) I would go a little bit further and say that the PSU is probably the most replaced "standard" part of a PC, followed by hard disks. I also a couple times repaired a PSU replacing this or that failed component, but it is simply not worth the time an…

Are you buying bottom of the barrel PSUs? I've had the same Corsair unit in three machines over the last decade. Works perfectly fine.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#138

Post by cesarb »

generatorguy wrote: post #40
sjwright wrote: post #30

Earlier quoted context omitted.

If you’re sending 1500 watts directly into a motherboard, something is probably wrong. Massive power draws (CPU, GPU) would always get their own direct connection, just as they do today. Apply this simple rule of thumb: watts become heat. The only major exception to this is where the power has exited the computer via USB or similar.

I haven't assembled a PC since the pentium 200 days. I recall hard drives, floppy drives, and the motherboard had their own power connections but not the CPU or GPU of the time. Still a single pin is probably something like a #18 gauge and would only be good for 10A before it gets too warm for comfort.

> I haven't assembled a PC since the pentium 200 days [...] had their own power connections but not the CPU or GPU of the time

That hasn't been true for a long time. Nearly every motherboard for many years has a separate "ATX12V" plug dedicated exclusively to the CPU voltage regulator input. According to Wikipedia (https://en.wikipedia.org/wiki/ATX12V), the first CPU which needed it was the Pentium 4 from the early 2000s.

As for the GPU, the PCI Express slot can only go up to 66W in the 12V rail (https://en.wikipedia.org/wiki/PCI_Express#Power), and that's a software-enabled special case for GPUs (the normal limit being 25W for long slots and 6W for the short x1 slots), so higher-power GPUs need one or even two separate power plugs.

Re: Intel is changing the future of power supplies with its ATX12VO spec

#139

Post by effie »

ChuckMcM wrote: post #88

I remember the days when Microsoft and Intel would host the "PCxx" spec (where xx was the last two digits of the year) and tell everyone what all the standards for desktop machines were going to be for the next few years. Those days are gone though. 12V rail PSUs are nice for a number of reasons but I always liked that you could feed your DC input from the AC side or a battery and have a "free" UPS at the same time.…

I am very much interested in this, using DC power sources is the future. How do I go around adding a 12V DC power supply to the ordinary ATX computer? Can you find some links for this?

Re: Intel is changing the future of power supplies with its ATX12VO spec

#140

Post by russdill »

simias wrote: post #132
russdill wrote: post #126

In one sense this feels like pushing the efficiency problem under the rug. There's a requirement for power supplies to meet a certain efficiency standard, and generating 3.3v and 5v rails are pushing that number down. Solution? Move that task to the motherboard where they won't count against the power supply efficiency requirement. Of course, from a purely engineering perspective, it really does make sense and it's o…

The motherboard "knows more" than the PSU though, it should be able to better deal with these idle power situations by shutting down things that aren't used anymore and powering them back up when needed. An external PSU would have tighter constraints regarding power availability and wouldn't be able to optimize the power profile quite as aggressively since they don't really know exactly what they're driving.

Many DC-DC supplies have auto-standby/idle modes that take care of this problem in an automatic way.
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