Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

According to my research, it sounds as though power efficiency concerns in recent years have driven some hardware manufacturers to create different power supplies and motherboards which are "12V-only". That is to say, power supplies have been created to supply 12-volt power exclusively, directly to the motherboard. Motherboards, in turn, have been built or modified specifically to receive 12-volt power only and convert it into usable power for the various 12-volt, 5-volt, and 3.3-volt hardware components within the single computer associated with that motherboard.

From a technical perspective, what are the costs and benefits of adopting such an approach for powering a computer?

What about from an economic perspective?

Is this type of hardware available to the mainstream?

share|improve this question

closed as not constructive by Randolph West, Xavierjazz, 8088, Indrek, random Aug 20 '12 at 16:23

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

I'm guessing this is mostly a cost-reduction strategy, since extra voltages in the PS cost money. But it's less efficient to down-regulate 12V to 5V than to generate the 5V directly, so it's likely not an energy-saving strategy. – Daniel R Hicks Aug 20 '12 at 3:45
OTOH with the power drawn by modern desktop CPU's (50W is typical) using a 12V supply means that you only have 4A currents; a 5V supply would need to provide 10A. That in turn requires thicker cables. Also, the CPU needs 1.3V or so, which means you need a downregulator anyway; might as well use a 12V->1.3V one. – MSalters Aug 20 '12 at 14:09

For Mini-ITX and other small form factor boards, the advantages of having onboard power regulation are cost reduction and form factor.

From a cost perspective, the price delta for two equivalent boards with/without onboard power is typically less than $10. Compared to the cost of even the least expensive picoPSU, that be a significant savings.

Eliminating the need for a full ATX connector on the board also allows the designer to be more flexible in component placement and reduce the Z-height of the board to newer Thin-ITX standards.

This is even more important for smaller form factors such as 3.5"/ECX and Pico-ITX, where adding a discreet power supply negates the miniscule packaging of the board.

The major disadvantage is the inability to use wide-input regulators (unless implemented onboard, as with the Intel DN2800MT "Marshalltown" board which can handle 8v-19v), and the extra bulk of an AC/DC brick instead of a straight AC/120v cord. Of note, some of the boards designed for desktop-class CPUs utilize a 19v adapter instead of 12v.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged .