Question Is there a way for a single PSU 8-pin slot to output more than 150W?

[GameDos]

Essentially I am considering upgrading from RTX 3090 to RTX 4090; however I have only two 8-pin PCIe cables plugged into my PSU (Corsair HX1200 80 PLUS PLATINUM).

I assumed since each cable can handle 288W, for a total of 576W, I could just use them without needing to install new power cables (since Im not even sure how Ill reach the PSU in an already-built machine).

However I was informed that each cable is essentially taking a max of 150W from the PSU. Is there no way to give them access to higher power?

In my PSU documentation, they mention "In the “SINGLE” position, the full output of the power supply’s +12V rail is available to any and all connectors, while in the “MULTIPLE” position, each individual connector has Over-Current Protection so no more than 40A of current can be delivered on any given cable."

https://assets.corsair.com/image/upload/corsairmedia/sys_master/productcontent/HX_Manual.pdf

Does that change anything? Or is it still the same issue.

 

[Eximo]

The GPU end of the cable is rated at 150W per 8-pin connector. The PSU end is rated for whatever Corsair designed into the PSU.

It is quite normal to modify the modular cabling on a PSU in a system that is already built. That is why they exist.

In your situation, you should actually just get a Corsar Type 4 12VHPWR cable.

https://www.corsair.com/us/en/p/pc-...5-0-12VHPWR-Type-4-PSU-Power-Cable-cp-8920284

 

[GameDos]

The GPU end of the cable is rated at 150W per 8-pin connector. The PSU end is rated for whatever Corsair designed into the PSU.

It is quite normal to modify the modular cabling on a PSU in a system that is already built. That is why they exist.

In your situation, you should actually just get a Corsar Type 4 12VHPWR cable.

https://www.corsair.com/us/en/p/pc-...5-0-12VHPWR-Type-4-PSU-Power-Cable-cp-8920284

Most likely not.

1) I heard Nvidia voids your warranty if you dont use their adapter.

2) I am already not looking forwards to installing one more cable, your suggestion would involve me REMOVING and then installing a more complex cable. Way more work. Might as well just install one more 8-pin cable and then plug the three cables into Nvidia's adapter;

 

[GameDos]

The GPU end of the cable is rated at 150W per 8-pin connector. The PSU end is rated for whatever Corsair designed into the PSU.

It is quite normal to modify the modular cabling on a PSU in a system that is already built. That is why they exist.

In your situation, you should actually just get a Corsar Type 4 12VHPWR cable.

https://www.corsair.com/us/en/p/pc-...5-0-12VHPWR-Type-4-PSU-Power-Cable-cp-8920284

Also, isnt the 150W just safety margin?

Like will it simply NOT draw more than 150W?

 

[Eximo]

Most likely not.

1) I heard Nvidia voids your warranty if you dont use their adapter.

2) I am already not looking forwards to installing one more cable, your suggestion would involve me REMOVING and then installing a more complex cable. Way more work. Might as well just install one more 8-pin cable and then plug the three cables into Nvidia's adapter;

3 8-pin will get you 450W only, so no overclocking or boost profile beyond 450W.

Corsair warranties the hardware in the case of you using the cable. They will send your card out for professional repair or cover a replacement in case something happens.

I think you are grossly over estimating the amount of work it would take to swap out the cables. Maybe a five minute job. Even faster if your chassis allows you to pull out the PSU through the rear to give yourself more room. Unless you are running some crazy small setup that still has room for a 1200 PSU and a 4090...

 

[Eximo]

Also, isnt the 150W just safety margin?

Like will it simply NOT draw more than 150W?

In the case of a 4090, there are limits set through the 4 sense pins on the 12VHPWR cable.

On something like your 3090, basically the card is going to draw what it wants. The PSU has limits on the rails. I would have to check on the HX1200 to see if they have OCP on each modular connector, I doubt it.

But, yes 150W is a guideline with large margins. It really depends on the wire gauge, soldered or crimped connections, etc. Though even cheap PSU will use at least 22 gauge wire and that should be about 60W per 12V wire (Depending on length), I believe Corsair uses 18 gauge, which is why they are safe to pull much higher wattage from their Type 4 8-pin.

Keep in mind that EPS 12V is rated for 336W, which is 4 12V wires, or 84W per wire. So 252W would be the expected limit of each Type-4 connection. If they say 288W, then that is probably about right.

But for the 4090 you must connect at least 3 8-pin to an adapter to get 450W total. Unless you re-wire the sense pins to force it to pull in from only 2 PCIe 8-pin. I wouldn't.

Personally I would get Corsair's Type 4, or one from Cablemod.

 

[--SID--]

The HCS terminals on the Corsair modular board are rated for 13A each pin. Three 12v pins makes 39A before it melts. Safe margin is 25A for each terminal. That's why Corsair uses two 8 pin terminals on the modular board for the 600w 12VHPWR cable. The first PCIe connector on a Corsair cable is also of HCS quality and can handle 300w without a problem.