4 ms·

to deliver 1500 watts at 12v through one pin would be 125 amps. 5 pins each with 25A I would think you’d want at least 14 gauge per pin and even then I think th

to deliver 1500 watts at 12v through one pin would be 125 amps. 5 pins each with 25A I would think you’d want at least 14 gauge per pin and even then I think they would be rather warm.

sjwright 7y ago
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.
- jmgao 7y ago
  PCIe specifies that you can get 75W from the connector, which adds up quickly.
- generatorguy 7y ago
  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.
  - x0 7y ago
    I always thought that was why the big ATX connector has multiple 12V wires, multiple GND wires, etc. To push heaps of current, but using a normal gauge of wire, rather than something huge.
  - cesarb 7y ago
    > 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 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 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.
klipklop 7y ago
Not all your power requirements will go directly to the motherboard though in that single connector. For example the GPU will have its own dedicated power plug(s). I would expect the motherboard to need < 500w for most systems.
- hinkley 7y ago
  Pretty sure his point still holds at 40 amps.

to deliver 1500 watts at 12v through one pin would be 125 amps. 5 pins each with 25A I would think you’d want at least 14 gauge per pin and even then I think they would be rather warm.

sjwright 7y ago

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.

jmgao 7y ago
PCIe specifies that you can get 75W from the connector, which adds up quickly.
generatorguy 7y ago
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.
- x0 7y ago
  I always thought that was why the big ATX connector has multiple 12V wires, multiple GND wires, etc. To push heaps of current, but using a normal gauge of wire, rather than something huge.
- cesarb 7y ago
  > 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 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 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.

klipklop 7y ago

Not all your power requirements will go directly to the motherboard though in that single connector. For example the GPU will have its own dedicated power plug(s). I would expect the motherboard to need < 500w for most systems.

hinkley 7y ago
Pretty sure his point still holds at 40 amps.