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What is the motivation of intel to want PSUs that are 12V only?
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epigramx:


https://www.intel.com/content/dam/www/public/us/en/documents/guides/single-rail-power-supply-platform-atx12vo-design-guide.pdf

The introduction claims that it is high time for PSUs to become more efficient.
But why would they want to make other circuits less efficient?
Rerouter:
Almost all high power computer switching supplies are built around using the 12V rail, with RAM and onboard peripherals barely pulling anything from the 5V rail, and due to the whole molex/sata thing, even 3.3V rails are getting less popular, as its not hard to locally down convert from 5V.

the RAM and other mid current loads on a motherboard are not hard to shift back to the 12V rail, in fact a number of overclocking boards already do this to save costs on unique parts when you need high current power stages.

When you pulling say 40A @ 12V, loosing 2-3W in switching losses for the lower power low voltage rails may be much better if you gain back 30W on the initial conversion of that high current load.
Zero999:
Because losses in cables, at very low voltages are high. Assuming everything else is equal, halving the voltage, results in four times the losses in cables. This is because P = I2R, reducing the voltage requires double the current, for the same power and 22 = 4.

Modern switched mode power supplies can be very efficient, so it make more sense to distribute a higher voltage and perform the voltage regulation, as close to the load, as possible. This is done with mains electricity, which is transmitted over long distances, at high voltages >100kV and stepped down to lower and lower voltages near the the load: 10kV is common around towns and cities, with 120V to 400V only traveling a few hundred metres.
epigramx:

--- Quote from: Rerouter on March 05, 2020, 10:13:43 am ---Almost all high power computer switching supplies are built around using the 12V rail, with RAM and onboard peripherals barely pulling anything from the 5V rail, and due to the whole molex/sata thing, even 3.3V rails are getting less popular, as its not hard to locally down convert from 5V.

the RAM and other mid current loads on a motherboard are not hard to shift back to the 12V rail, in fact a number of overclocking boards already do this to save costs on unique parts when you need high current power stages.

When you pulling say 40A @ 12V, loosing 2-3W in switching losses for the lower power low voltage rails may be much better if you gain back 30W on the initial conversion of that high current load.

--- End quote ---
So you're implying they're going to favor very high power PCs with this and consider low power desktops a minority.
bd139:
I was getting all excited when I saw this mostly from the vain hope that they'd get rid of Molex connectors. But nope :(

As for the multiple voltages, this is a legacy hang back going back as far as the 1980s. Even latest normal ATX spec has -12V still. That needs to die.

If they introduce single voltage that means smaller, simpler, more reliable power supplies, easier to manage power supply efficiency etc. And every device can ship with its own slave switching converters to get whatever voltages it needs out. The biggest consumer in my PC is currently yanking 116.3A @ 1.475V which is quite frankly a shit load of current so I'd rather have that being converter right next to where it is being used which is exactly what's happening now.

Also if everything is 12V, consider laptops etc. If all peripherals standardise on that we're getting smaller desktop PCs too which would be mostly cooling rather than fat bundles of snakes in a gigantic box.
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