Gigabyte rtx 4090 gaming oc can it run on only 3 8 pins?

[Tomgang]

So now it's me that need to answer a question.

I know some rtx 4090 like the fe rtx 4090 can run on only 3 8 pins connectors. But the downsides is that the max power target is locked to max 450 watt and not the 600 watt max when 4 8 pins are in use.

But does any one know if my gigabyte rtx 4090 gaming oc can do the same (it has 4 8 pins connectors)?

I can live with losing the highest power target possible. The performance gain vs. Watt use is hardly worth it any way to raise power target over stock. Mostly I run it undervoltet any way.

My psu only has 4 6/8 pins connectors and in near future I might need 1 of these 8 pins to power a second gpu that needs a 8 pin (rtx 4060), leaving only 3 8 pins for my rtx 4090.

Right now I use a Cablemods cable to connect to my rtx 4090, but have the ugly stock adapter if need to run only 3 8 pins.

 

[nguyen]

Yes you can run 3x8pins on the 4090, the card can will automatically limit TDP to 450W

 

[P4-630]

First world problem...

Get a PSU with more GPU connectors.

 

[Tomgang]

First world problem...

Get a PSU with more GPU connectors.

Not possible in my case. The psu I have, is the only one in the world for what I know that can run two systems with one psu. Buying another psu will render one of my systems unusable in dual system build, as my case don't support two systems and two psu at the same time.

So not possible in my case.

 

[Vayra86]

Not possible in my case. The psu I have, is the only one in the world for what I know that can run two systems with one psu. Buying another psu will render one of my systems unusable in dual system build, as my case don't support two systems and two psu at the same time.

So not possible in my case.

Now we know how these YT videos come into existence where someone swapped 4090 for a 7900XTX and preferred it

 

[yzonker]

Just buy a 3rd party cable like Fasgear, Cablemod, etc... You can run 600w with 3x8pin with one of those.

 

[Tomgang]

Just buy a 3rd party cable like Fasgear, Cablemod, etc... You can run 600w with 3x8pin with one of those.

Thats not a good advice.

Rtx 4090 will be locked to 450 watts with only 3 8 pins. I have a cablemods cable all ready.

If what you say is true. You have a potential fire hazard. Each 8 pins is rated at 150 watts max pull. 600 watt from 3 8 pins is 200 watt from each connector and risk overloading connector or psu and either melt connectors or damage psu if the psu does not cut out from overload first.

Stock adaptor for these cards you can run with 3 8 pins but with power target locked to 450 watt max and when all 4 8 pins are in you have access to the 600 watt limit. It should not be possible with cablemods cable to do your suggestions, however cablemods cable might be wired differently that will cheat the card to think its safe to unlock the 600 watt limit,while should not do it. Because as explained above.

In short you are litterly suggests me to make a firehazard or risk of hardware damage, inside my pc.

 

[GerKNG]

If what you say is true. You have a potential fire hazard. Each 8 pins is rated at 150 watts max pull. 600 watt from 3 8 pins is 200 watt from each connector and risk overloading connector or psu and either melt connectors or damage psu if the psu does not cut out from overload first.

PSU sided 8 Pins are rated for 28A/336W, GPU sided are 150W

 

[yzonker]

Thats not a good advice.

Rtx 4090 will be locked to 450 watts with only 3 8 pins. I have a cablemods cable all ready.

If what you say is true. You have a potential fire hazard. Each 8 pins is rated at 150 watts max pull. 600 watt from 3 8 pins is 200 watt from each connector and risk overloading connector or psu and either melt connectors or damage psu if the psu does not cut out from overload first.

Stock adaptor for these cards you can run with 3 8 pins but with power target locked to 450 watt max and when all 4 8 pins are in you have access to the 600 watt limit. It should not be possible with cablemods cable to do your suggestions, however cablemods cable might be wired differently that will cheat the card to think its safe to unlock the 600 watt limit,while should not do it. Because as explained above.

In short you are litterly suggests me to make a firehazard or risk of hardware damage, inside my pc.

Sigh... Sometimes I wonder why I bother.

Do you think Corsair is setting themselves up for a lawsuit over this cable,

12VHPWR Cable | 600W PCIe 5.0 Power Adapter Cable

The official CORSAIR 600W PCIe 5.0 / Gen 5 12VHPWR PSU Power Cable delivers power from CORSAIR Type-4 PSUs to the most advanced PCIe 5.0 graphics cards.

www.corsair.com

Or Fasgear,

Fasgear PCI-e Gen 5.0 Power Cable for EVGA/ASUS/Seasonic Power Supply - 70cm 12VHPWR 16pin (12+4) to PCIE 3x8pin (6+2) Male Cable - for RTX 3090 Ti & 4080 4090 Graphics Card

Fasgear PCI-e Gen 5.0 Power Cable for EVGA/ASUS/Seasonic Power Supply - 70cm 12VHPWR 16pin (12+4) to PCIE 3x8pin (6+2) Male Cable - for RTX 3090 Ti & 4080 4090 Graphics Card

m.fasgear.com

Or Seasonic,

Seasonic 12VHPWR Cable

Seasonic 12VHPWR Cable

seasonic.com

Care to guess why these are all being sold? Because the PSU side 8pin cable is rated at 300w. Try using Google before posting a bunch of non-sense.

 

[Dr. Dro]

Thats not a good advice.

Rtx 4090 will be locked to 450 watts with only 3 8 pins. I have a cablemods cable all ready.

If what you say is true. You have a potential fire hazard. Each 8 pins is rated at 150 watts max pull. 600 watt from 3 8 pins is 200 watt from each connector and risk overloading connector or psu and either melt connectors or damage psu if the psu does not cut out from overload first.

Stock adaptor for these cards you can run with 3 8 pins but with power target locked to 450 watt max and when all 4 8 pins are in you have access to the 600 watt limit. It should not be possible with cablemods cable to do your suggestions, however cablemods cable might be wired differently that will cheat the card to think its safe to unlock the 600 watt limit,while should not do it. Because as explained above.

In short you are litterly suggests me to make a firehazard or risk of hardware damage, inside my pc.

It is true, and if you know what you are doing, it is not a fire hazard. When using the NVIDIA power adapter bundled with the graphics card, there is a power control IC which limits the maximum range to 450 W or 600 W, depending on the amount of connectors that are installed.

Here is a diagram (from Igor's site) on how the 12VHPWR adapter from Nvidia works:

Myth Busted: This is how NVIDIA’s 4-way adapter for the 12VHPWR port of the GeForce RTX 4090 really works! | igor´sLAB

Who doesn’t know it, the funny adapter from NVIDIA, with which you can merge four PCIe 6+2 pin cables to be able to run graphics cards with up to 600 watts? If you only connect three plugs…

www.igorslab.de

As noted on Igor's blog, you'll find that this IC is entirely optional and that the sense pins being connected to ground are what dictates how much power the connector will allow. That said, even 2x PSU-side to 12VHPWR cables are technically fully capable of 600 W, as long as the wire gauge is large enough to handle the load and your PSU is capable of feeding that much power into the socket. Most... can't do that, and there lies the catch, use a crappy thin gauge cable and you got an IED in your hands. The only way to make absolutely sure the PSU is capable of outputting all this power through one cable is to buy an ATX 3.0 PSU with 12VHPWR native, your alternative being a high quality, large gauge cable with 3 or 4 plugs at the other end. Which will work just fine.

CableMod's sleeved Pro-series 16 AWG cables should be plenty enough for 600 W. I ordered one that's 3x 8-pin PSU-side to 12VHPWR native for my Strix 4080, and it's on its way from America as we speak. Of course, for my card, 450 W would be plenty as it is, so it's a little different story from your case.

It seems that if you do not want to replace your power supply, you will need to source either a cable designed for your PSU, or acquire the 3x 6+2 PCIe to 12VHPWR that is bundled with the RTX 4080 - and use that with the 450 W limitation instead.

 

[Tomgang]

Just buy a 3rd party cable like Fasgear, Cablemod, etc... You can run 600w with 3x8pin with one of those.

Sigh... Sometimes I wonder why I bother.

Do you think Corsair is setting themselves up for a lawsuit over this cable,

12VHPWR Cable | 600W PCIe 5.0 Power Adapter Cable

The official CORSAIR 600W PCIe 5.0 / Gen 5 12VHPWR PSU Power Cable delivers power from CORSAIR Type-4 PSUs to the most advanced PCIe 5.0 graphics cards.

www.corsair.com

Or Fasgear,

Fasgear PCI-e Gen 5.0 Power Cable for EVGA/ASUS/Seasonic Power Supply - 70cm 12VHPWR 16pin (12+4) to PCIE 3x8pin (6+2) Male Cable - for RTX 3090 Ti & 4080 4090 Graphics Card

Fasgear PCI-e Gen 5.0 Power Cable for EVGA/ASUS/Seasonic Power Supply - 70cm 12VHPWR 16pin (12+4) to PCIE 3x8pin (6+2) Male Cable - for RTX 3090 Ti & 4080 4090 Graphics Card

m.fasgear.com

Or Seasonic,

Seasonic 12VHPWR Cable

Seasonic 12VHPWR Cable

seasonic.com

Care to guess why these are all being sold? Because the PSU side 8pin cable is rated at 300w. Try using Google before posting a bunch of non-sense.

It is true, and if you know what you are doing, it is not a fire hazard. When using the NVIDIA power adapter bundled with the graphics card, there is a power control IC which limits the maximum range to 450 W or 600 W, depending on the amount of connectors that are installed.

Here is a diagram (from Igor's site) on how the 12VHPWR adapter from Nvidia works:

View attachment 307381

Myth Busted: This is how NVIDIA’s 4-way adapter for the 12VHPWR port of the GeForce RTX 4090 really works! | igor´sLAB

Who doesn’t know it, the funny adapter from NVIDIA, with which you can merge four PCIe 6+2 pin cables to be able to run graphics cards with up to 600 watts? If you only connect three plugs…

www.igorslab.de

As noted on Igor's blog, you'll find that this IC is entirely optional and that the sense pins being connected to ground are what dictates how much power the connector will allow. That said, even 2x PSU-side to 12VHPWR cables are technically fully capable of 600 W, as long as the wire gauge is large enough to handle the load and your PSU is capable of feeding that much power into the socket. Most... can't do that, and there lies the catch, use a crappy thin gauge cable and you got an IED in your hands. The only way to make absolutely sure the PSU is capable of outputting all this power through one cable is to buy an ATX 3.0 PSU with 12VHPWR native, your alternative being a high quality, large gauge cable with 3 or 4 plugs at the other end. Which will work just fine.

CableMod's sleeved Pro-series 16 AWG cables should be plenty enough for 600 W. I ordered one that's 3x 8-pin PSU-side to 12VHPWR native for my Strix 4080, and it's on its way from America as we speak. Of course, for my card, 450 W would be plenty as it is, so it's a little different story from your case.

It seems that if you do not want to replace your power supply, you will need to source either a cable designed for your PSU, or acquire the 3x 6+2 PCIe to 12VHPWR that is bundled with the RTX 4080 - and use that with the 450 W limitation instead.

Sounds like i might have been wrong on the psu side. But Stiil pulling over the rated 150 watt on the gpu side sounds like a risk of at least melted connectors.

I have as told all ready a cablemods cable specially made to fit my gpu and psu. It has 4 8 pins to the psu side and that new connector to plug in to the gpu. So going down to 3 8 pins and still pull 600 wattsv just sounds as a bad idea to what ever its possible or not.

I will have to investigate this further and maybe contact cablemods about my cable or if i would need another one to pull this off safely then.

To get back to topic. I really dont need the 600 watt capability. The last watts really does not give that more performance so its worth it. Its more like is it sate to run 3 8 pins and stick to 450 watts with my current cable.

 

[oxrufiioxo]

As long as you buy a quality cable a 2x 8pin to 16pin is fine. Cablemod sells one now.

 

[Toothless]

Could always just use a low power GPU for the 2nd desktop, like that only needs PCI power. Ya really got a first world problem here.

Or engineer a mount for a SFX PSU.

 

[yzonker]

Sounds like i might have been wrong on the psu side. But Stiil pulling over the rated 150 watt on the gpu side sounds like a risk of at least melted connectors.

I have as told all ready a cablemods cable specially made to fit my gpu and psu. It has 4 8 pins to the psu side and that new connector to plug in to the gpu. So going down to 3 8 pins and still pull 600 wattsv just sounds as a bad idea to what ever its possible or not.

I will have to investigate this further and maybe contact cablemods about my cable or if i would need another one to pull this off safely then.

To get back to topic. I really dont need the 600 watt capability. The last watts really does not give that more performance so its worth it. Its more like is it sate to run 3 8 pins and stick to 450 watts with my current cable.

Sorry if I came on a bit strong, but I just get that kind of response a lot and get tired of it.

But yea, CM has a 3x8pin also if you're more comfortable with that (versus a 2x8pin). A lot of people are running them and I haven't seen a single failure reported on the 8pin side. We of course have seen failures in the 12vhpwr connector which is kinda ironic.

 

[Dr. Dro]

Sounds like i might have been wrong on the psu side. But Stiil pulling over the rated 150 watt on the gpu side sounds like a risk of at least melted connectors.

I have as told all ready a cablemods cable specially made to fit my gpu and psu. It has 4 8 pins to the psu side and that new connector to plug in to the gpu. So going down to 3 8 pins and still pull 600 wattsv just sounds as a bad idea to what ever its possible or not.

I will have to investigate this further and maybe contact cablemods about my cable or if i would need another one to pull this off safely then.

To get back to topic. I really dont need the 600 watt capability. The last watts really does not give that more performance so its worth it. Its more like is it sate to run 3 8 pins and stick to 450 watts with my current cable.

That's because all the power only goes through the pins highlighted in the diagram above. It's really a messy conversion, unless a custom fit cable is made. They have this 4x PSU side from the Basics line for my power supply as well, but from what I've seen, it is not necessary even for use with the RTX 4090. It helps that my 1300 G2 has a massive single 12V rail, I suppose.

Considered my card has a maximum BIOS power limit of 420 W (and this quite generous as far as RTX 4080 is concerned), I went ahead with the sleeved 3x PSU side Pro cable. It would work great even with 600W 4090's, anyway.