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For at least ~20 years, the typical solution for ATX power supplies has been to make one big 12V rail, and then tack on up to about 120W of converters to step d
by wtallis 3y ago
For at least ~20 years, the typical solution for ATX power supplies has been to make one big 12V rail, and then tack on up to about 120W of converters to step down from 12V to 5V and 3.3V. In practice, this has meant that anyone running less than a dozen disk drives has excess capacity on their 5V rail, but no capacity from the 12V rail was sacrificed to provide that.
There was a time when the 5V and 3.3V rails on ATX power supplies weren't vestigial, but that era was shorter than the current era of all the major high-power components using a 12V supply.
- toast0 3y agoSomewhere in the last two decades, multiple 12v rails was popular, but I think we've gone back to single rails.
- wtallis 3y agoFor a while, some PSUs were dividing their single 12V rail into separate outputs with individual current limits, to more closely adhere to older ATX standards. Consumers were not interested in managing the complexity of balancing power between virtual rails while CPU and GPU power were skyrocketing.