older psu with dual 12v rails. Do both rails power the cpu?

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Kdawg

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I have an old Earthwatts 380 which was built by seasonic. Has dual 12v rails at 17A.

specs say one 12v powers motherboard and peripherals, the other 12v powers cpu.

but with it all plugged in, do both 12v rails power the cpu still?

i mean how many amps are available to the cpu?
 
It's 17A on either rail or ~320W on both combined. So if you exceed 17A (204W at 12V) on either rail, or exceed 320W combined, it will shut off. The rails are separate, though, supposedly. You'd have to ask someone familiar with PSU circuits to tell you how that's accomplished.
 
where does the cpu draw its power though?

If i run a 12600k at max load, it could exceed 204w, but does it then pull extra power from the other rail then?
 
Kdawg said:
where does the cpu draw its power though?

If i run a 12600k at max load, it could exceed 204w, but does it then pull extra power from the other rail then?
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No, it either shuts down the PSU, or it blows up, depending on how well made the power supply is. If it doesn't do either, then it's a ticking time bomb...
 
Yeah, new PSU would be...uhh...a good idea. With a 200W GPU, you'd be limited to 120w for the CPU. 200w CPU, you'd be limited to 120w GPU. It's generally not good all around.
 
Honestly if you have picked up a 12600k and mobo. You should be in the market for a new psu. Why put new hardware in a system and use a old psu? If it was a larger rated quality older psu then I would think different.
 
As others said, you should really consider a new PSU.

That said, virtually all multi-rail PSUs are just single rail PSUs with separate OCPs for each set of connectors to create the multiple rails. The only true multirail consumer PSU I can think of was the first generation Corsair HX1000. So while you won't be overloading the rail as long as you stay below 380 watts, you will overload the OCP, which may or may not cause the PSU to shut down. I'm not sure if overloading the OCP has any fire risks.
 
I'm all about re-using old power supplies but that Earthwatts 380 was a terrible model. I had several of them and they all died far earlier than they should have.

I believe on that PSU that one 12V rail is powering the CPU (mainly via the ATX12V connector) and the other is for peripherals via SATA/Molex. Not sure which rail the 6-pin PCIe power pulls from, but probably the same rail as the SATA/Molex. This was an early-generation ATX12V PSU and still supplied a fair bit of of power on the 5V rail.
 
Antec used garbage OST and Fuhjyyu caps in those models so they weren't good new, but after a decade+ I'm surprised that computer will even boot with that PSU. Replace it ASAP.
 
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