Comment by johnwalkr | Hacker News Reader

Comment by johnwalkr | Hacker News Reader

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A higher input voltage may eventually be used but a standard PC power supply only has 12V and lower (5V and 3.3V) available, so they'd need to use a new type of power supply or an external power supply, both of which are tough sells.

On the other hand, the voltages used inside a GPU are around 1V, and a higher input voltage introduces lower efficiency in the local conversion.

12V is only really used because historically it was available with relatively high power capacity in order to supply 12V motors in disk drives and fans. If power supplies were designed from the ground-up for power-hungry CPUs and GPUs, you could make an argument for higher voltage, but you could also make an argument for lower voltage. Or for the 12V, either because it's already a good compromise value, or because it's not worth going against the inertia of existing standards. FWIW there is a new standard for power supplies and it is 12V only with no lower or higher voltage outputs.

Lower voltage would be OK, but then all of the cables and plugs would need to be redesigned. And there would still need to be for voltage switching unless we start adding a protocol and have PSU switch voltage dynamically... which is also not efficient.

Since they went so far to create a new cable which wont be available on old PSU they would have easily extended that slightly and introduced an entirely new PSU class which has a new voltage also. But now they went the easy route and it failed which is even worse as they will have to redesign it now instead of it being safely done the first time.

There are versions of the cables (and adapters) that work on older PSUs, although new PSUs are starting to come with the same connector that new GPUs have.

Anyway there are pros and cons to using 12V, or lower or higher, and anything except 12V would require a new PSU so it's a hard sell. But even without that detail, I have a feeling 12V is a reasonable choice anyway, not too low or high for conversion either in the PSU or in the GPU or other component.

In any case, at the end of the day sending 12V from the PSU to GPU is easy. The connector used here is bad, either by design or manufacturing quality, but surely the solution can be a better housing and/or sockets on the cable side connectors instead of a different voltage.

> Lower voltage would be OK, but then all of the cables and plugs would need to be redesigned. And there would still need to be for voltage switching unless we start adding a protocol and have PSU switch voltage dynamically... which is also not efficient.

It's not like that. It's a design where PSU only provides 12V to motherboard and motherboard provides the rest. Only location of those connectors change. It's called ATX12VO.

In modern PC almost nothing draws from 3v3 rail, not even RAM. I'm pretty sure nothing draws 3v3 directly from PSU at all today.

5v rail directly from PSU only used for SATA drives.

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