Increasing GPU power connectors amount: how hard is it to do and how do I make sure it makes sense?

[Beginner Macro Device]

As title says, I'm wondering if buying a GPU with, say, two 8-pin power connectors to ultimately solder a third one to it so I could get my OC potential higher and per-cable load lower makes any sense.

I'm aware of what VRMs are and how to make sure it can handle another one 8-pin connector.
I'm also aware that no double 8-pin GPU is enough for what I want to do and triple 8-pin GPUs are not an easy find so I'm considering a plan B.
I also don't give a zap about warranty and my RMA eligibility. I am going full YOLO with this purchase.

What I'm not aware of is what I should consider besides VRM and temperatures. I know how to make it cool enough. I don't know what else matters. I also don't know how to make GPU "see" the third power connector and actually use it.

The most likely frankensteining candidate is an RX 6900 XT with the PCB of the reference design. Less likely, a 6800 XT.

Answers like "it's stupid" are ignored because I know it's stupid and answers like "get a job" are also ignored because getting a job is also stupid.

 

[Vya Domus]

There are probably other ICs missing on the board so I doubt it would work just by simply slapping another connector. People usually achieve what you want to do with one of those external VRMs that you solder on bypassing the board's VRM.

It wouldn't make a difference anyway unless you can get a different BIOS that would have a higher power limit.

 

[Beginner Macro Device]

It wouldn't make a difference anyway unless you can get a different BIOS that would have a higher power limit.

BIOS flashing is dead. What makes short work of this limitation is MorePowerTool.

I doubt it would work just by simply slapping another connector

I know it won't work and I know I need to short some jumpers, solder some connections or whatever for that to actually start breathing. I know it's not plug'n'play, I just don't know what exactly I need to do.

 

[DR4G00N]

I'm also aware that no double 8-pin GPU is enough for what I want to do

The power connectors can easily handle more than the spec so I don't think it's going to be an issue. The spec is in place because of the terrible quality psu's that are out there that cheap out on cable size. With a high quality psu using 18-16 AWG cables each connector can handle 250W at least (that goes for both 6 & 8-pin since they both have the same number of 12V connections).

Also what kind of power are you expecting out of a 6900 XT? Even under the worst case scenario I wouldn't expect more than 450W at most.

 

[Noci]

Besides what Vya Domus & DR4G00N mentioned, the actual copper traces in the PCB will have a limit on how many amps they can conduct without excessively heating up or have a current leakage.
Sure, with the design of the PCB they'll account for some room of overhead but I doubt that will be heading way to 50%.

So if you find a 'simple' way to overcome the extra power injection to the card, the physical limitations of the PCB are probably your party killer. Nevertheless an interresting challenge, but it would be a shame if you send a RX 6900 XT to graphics heaven

 

[Beginner Macro Device]

The power connectors can easily handle more than the spec so I don't think it's going to be an issue

I tested my connectors and "easily handle 250 W" isn't about them. Roasted exactly the same cables by constant 210 W per each in one month. This is my YOLO machine and this is why, instead of getting a more power efficient GPU/beefier cables/doing whatever REASONABLE I decided I will just slot an extra 8-pin connector if I don't find a 3x8-pin GPU that I want. Don't know how much sense it makes but at least I'm honest with myself and already settled with that being a possibly total YOLO move.

the actual copper traces in the PCB will have a limit on how many amps they can conduct without excessively heating up or have a current leakage.

This is exactly what I was asking for. How do I know that? How do I evaluate the maximum damage I can inflict without being punished for that?

it would be a shame if you send a RX 6900 XT to graphics heaven

Anything goes. YOHOHO!

 

[Noci]

I tested my connectors and "easily handle 250 W" isn't about them. Roasted exactly the same cables by constant 210 W per each in one month. This is my YOLO machine and this is why, instead of getting a more power efficient GPU/beefier cables/doing whatever REASONABLE I decided I will just slot an extra 8-pin connector if I don't find a 3x8-pin GPU that I want. Don't know how much sense it makes but at least I'm honest with myself and already settled with that being a possibly total YOLO move.

This is exactly what I was asking for. How do I know that? How do I evaluate the maximum damage I can inflict without being punished for that?

Anything goes. YOHOHO!

Afraid that getting the blueprints from the PCB manufacterer is a mission impossible. With that you might have some insight in the conducting capacities of the copper traces if it is even published what the physical properties are.

Looks like you'll have to use the good old 'trail & error' method, to go where no man has gone before.

Scotty, we need more power...

Poor graphics card...

 

[Beginner Macro Device]

Afraid that getting the blueprints from the PCB manufacterer is a mission impossible.

I think reverse engineering makes more sense than asking for what seems to be a commercial secret. I will ask local repairmen, they might know where to look or know a guy who knows a guy...

Looks like you'll have to use the good old 'trail & error' method, to go where no man has gone before.

Even if things turn this way I'm ready. Not sure if the GPU is but the poor thing will never be forgotten.

 

[Assimilator]

I know it won't work and I know I need to short some jumpers, solder some connections or whatever for that to actually start breathing.

If it was as easy as that everyone would be doing it. It's not.

I know it's not plug'n'play, I just don't know what exactly I need to do.

And neither do we, since we didn't design your GPU.

 

[Beginner Macro Device]

If it was as easy as that everyone would be doing it. It's not.

Some guys fixed the 3070 series GPUs by injecting 16 GB VRAM on them. That wasn't straightforward and cost a lot of work but it's proved to be possible. I don't think my interest differs THAT much.

And neither do we, since we didn't design your GPU.

Some people don't need to design GPUs to understand what does what. They are called expert technicians.

 

[Count von Schwalbe]

If a 6900 XT is your target, there are at least 12 designs (according to pcpartpicker) that come with 3x8-pin power connectors from the factory.

IDK about cross-flashing or modifying the BIOS - Nvidia cards have been "jailbroken" but not Radeon afaik - but a relatively simple shunt mod should allow you to achieve a higher power limit.

 

[Beginner Macro Device]

there are at least 12 designs (according to pcpartpicker) that come with 3x8-pin power connectors from the factory.

We don't have BNIB 6900 XTs for reasonable money. Like, $1200 for a 6900 XT, are you serious about that? 150 quid more, and I'm golden with a 4080.
We also don't have much refurbished/used 3x8-pin 6900 XTs going on. They are rare and not usually from good sellers.

That's why I am a little bit concerned I might have to butcher a 2x8-pin GPU.

IDK about cross-flashing or modifying the BIOS

Not the concern and not needed. I just want to make sure my cables won't melt. Having power limit increased is not an issue provided I didn't destroy the GPU whilst modding.

 

[Assimilator]

Some guys fixed the 3070 series GPUs by injecting 16 GB VRAM on them. That wasn't straightforward and cost a lot of work but it's proved to be possible. I don't think my interest differs THAT much.

That was literally a case of installing memory chips of the same capacity into the empty spaces on the PCB, which is not so much rocket science as putting pieces into a puzzle. Absent power circuitry is a different kettle of fish, especially if the PCB in question was designed to not have it.

Some people don't need to design GPUs to understand what does what. They are called expert technicians.

They do, however, need to analyse the specific graphics card PCB to determine what might be able to be done. There isn't a one-size-fits-all recipe, because there can't be.

 

[Beginner Macro Device]

That was literally a case of installing memory chips of the same capacity into the empty spaces on the PCB

If you cared to read what they have done you'd not spread such nonsense. It's not just planting VRAM, it's also reprogramming the whole PCB in order for these VRAM sticks to be recognised by the GPU and to be working correctly. Like you said, if that was so easy it would be done by everyone.

 

[Count von Schwalbe]

We don't have BNIB 6900 XTs for reasonable money. Like, $1200 for a 6900 XT, are you serious about that? 50 quid more, and I'm golden with a 4080.
We also don't have much refurbished/used 3x8-pin 6900 XTs going on. They are rare and not usually from good sellers.

That's why I am a little bit concerned I might have to butcher a 2x8-pin GPU.

Not the concern and not needed. I just want to make sure my cables won't melt. Having power limit increased is not an issue provided I didn't destroy the GPU whilst modding.

My bad, I thought you wanted to increase power limit. FWIW, the TOXIC Extreme Edition from Sapphire has 2x8+1x6 pin, and a 430w TDP.

Here's the list, good luck:

You might be able to find waterblock compatibility charts or information that shows what lower-tier GPU's use the same PCB as the top-end ones shown above. That would be your best bet for finding a compatible PCB.

I expect some of the power delivery circuitry will be missing in addition to the connector; that will take some detailed analysis to figure out.

If your concern is strictly the PSU cables, not the connectors themselves, you could create a frankenconnector that adapts 3x8-pin to 2x8-pin connector. I am not sure about load balancing across cables though.

 

[Noci]

By the way, if you're only concerned the 2 x 8-pin PCIe cables are not up to the task, it is relatively simple to custom make a set of cables yourself.
Cables with a little higher capacity are widely available as are crimping tools, terminals and plugs.

Still trying to save that card from a melt down

 

[dj-electric]

A napkin math calculation of 2x8PIN using contemporary PSUs and connectors mean you are given a current capability of roughly 60A @ 25c ambient.
OP, 60A @ 12V is 720W. Soldering another connector is not going to do jack. Usually extreme overclocking cools the board and the connectors down well below ambient, which grants you an even greater current capability.

 

[Wirko]

I just want to make sure my cables won't melt.

If that's all you're concerned about, just solder another connector, or two of them, to the opposite side of the PCB, on the same solder pads as existing connectors. The layout of pins will be mirrored so you'll have to modify the new cable(s) but that's only going to enhance the exoticness of your setup, right?

 

[Beginner Macro Device]

If that's all you're concerned about, just solder another connector, or two of them, to the opposite side of the PCB, on the same solder pads as existing connectors. The layout of pins will be mirrored so you'll have to modify the new cable(s) but that's only going to enhance the exoticness of your setup, right?

Zamn, that's genius. Will do.

 

[ty_ger]

Just run more or bigger wires by whatever means you prefer. That's elementary. The real limitation is the VRM, the PCB, the firmware, the cooling, and everything else.

If you really want to uncork it, cut the VRM out of the circuit and solder on an e-power board. Otherwise, what you have doesn't need anything more that a decent PSU, decent cables, and some ice water.

This is a silly thread.

 

[Wirko]

Zamn, that's genius. Will do.

You're probably aware but it doesn't hurt to mention: solder is brittle, and through-hole components can't withstand much mechanical stress and strain when mounted the wrong way. If you do that, route and fasten the cables so as to not pull strongly on the connectors in any direction.

 

[AleXXX666]

As title says, I'm wondering if buying a GPU with, say, two 8-pin power connectors to ultimately solder a third one to it so I could get my OC potential higher and per-cable load lower makes any sense.

I'm aware of what VRMs are and how to make sure it can handle another one 8-pin connector.
I'm also aware that no double 8-pin GPU is enough for what I want to do and triple 8-pin GPUs are not an easy find so I'm considering a plan B.
I also don't give a zap about warranty and my RMA eligibility. I am going full YOLO with this purchase.

What I'm not aware of is what I should consider besides VRM and temperatures. I know how to make it cool enough. I don't know what else matters. I also don't know how to make GPU "see" the third power connector and actually use it.

The most likely frankensteining candidate is an RX 6900 XT with the PCB of the reference design. Less likely, a 6800 XT.

Answers like "it's stupid" are ignored because I know it's stupid and answers like "get a job" are also ignored because getting a job is also stupid.

and you are aware that card will have "golden sample" gpu die and mem chips too? prob thing will cost already like a budget variant of next level gpu lol, so it's just "fun time".
it's like adding another turbine for some sh..tty 1.0 cc car engine hoping that it will be better than plain 2.0 at least lol

 

[GerKNG]

Do you even know what you want to achieve with that idea?
More current is basically irrelevant you need to go beyond destructive VCore to even achieve a couple % of extra clockspeed.
I have a 6800XT pulling over 420W and all it gave me was ~100MHz beyond what i could achieve with the standard 284W, mandatory watercooling and a new PSU because my HX1200i trips OCP...
This is nonsense.