Cable maker advises against using old 12VHPWR cables with RTX 50-series GPUs

Graphics Card running Moddiy 12V-2x6 RTX 50 series compatible custom cable

(Image credit: Moddiy)

After one of its cables was blamed in the first credible report of an RTX 5090 power connector melting, third-party power supply cable maker Moddiy has warned RTX 50-series (Blackwell) GPU owners not to use its old 12VHPWR custom cables made before 2025 with Nvidia's latest Blackwell GPUs. In a support page detailing the matter, Moddiy says that all of its cables made in 2025 have been validated for the RTX 50-series, but the 2024 and earlier cables are another matter.

Moddiy's 2025 cables have been upgraded to cope with the higher power requirements of the RTX 50-series, specifically the RTX 5090 and RTX 5090D. Its new 2025 cables reportedly incorporate "significant advancements," such as enhanced terminal and connector housing materials and thicker wires. These changes have been made to provide an additional safety buffer and prevent accidents.

The new 2025 cables are also manufactured according to the latest 12V-2x6 specification. Older cables made in 2024 or earlier were based on the original 12VHPWR standard.

The support page provides a listing of new cables with RTX 50-series support that Moddiy is producing. The new cable has all the bells and whistles, sporting ATX 3.1 and PCIe 5.1 support, a 675W power rating, and a 12V-2x6 specification. Critically, it has the latest "H++" moniker, the identification for cables boasting the upgraded 12V-2x6 power spec. Cables featuring the "H+" identification were designed with the older 12VHPWR power spec in mind.

Moddiy support page stating 12V-2x6 recommendation for RTX 50 GPUs — (Image credit: Moddiy)

The new adapter cable has three 8-pin input connectors that merge into a single 12V-2x6 connector on the other side. This cable is designed for older power supplies that don't have a dedicated 12V-2x6 connection and allows users to ditch (or at least not user) any adapters that Nvidia and its partners ship with RTX 50-series GPUs.

The transition to the 12V-2x6 standard (on the cable side) should help eliminate any potential damage caused by the high power draw of power-hungry RTX 50-series GPUs such as the RTX 5090. The 12V-2x6 standard is nothing new; Nvidia began transitioning its GPUs to the spec as early as 2023, starting with the RTX 4070 and RTX 4090. However, the higher power draw of the RTX 5090 is now a big enough reason for cable makers like Moddiy to recommend only using the newer 12V-2x6 standard on the physical cables themselves.

Concerns over the possibility of the RTX 50-series 12V-2x6 power connectors overheating and causing them to catch fire increased when the first credible report of an RTX 5090 FE with a melted connector appeared online. The culprit was allegedly Moddiy's third-party cable, which was only rated at 600 watts and was previously used on an RTX 4090.

After the incident, German overclocker and PC enthusiast Der8auer ran his testing. His tests revealed that a RTX 5090 cable overheated up to 150C on some wires due to uneven power distribution on all cables. However, system integrator Falcon Northwest states that it has not been able to replicate the melting issues seen from Der8auer or the initial report that set all of this in motion.

Our take: Use a 12V-2x6 cable. It's that simple. While 12VHPWR is physically compatible with the 12V-2x6 socket, and vice versa, there's no good reason to risk using a cable with the older specification on a new GPU, particularly on the RTX 5090 that has a base MSRP of $1,999 but currently sells out virtually instantly and has prices of $5,000 and more on places like eBay.

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Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.

9 Comments Comment from the forums

hotaru251

so sounds liek a moot point...if the older 12vhp cables were up to standard then they should handle 600w still....if the gpu itself is damaging them then that is STILL a very big issue as means GPU aren't following the standards (as in pulling over that)
Reply
Papusan

Does this means MODDIY now will use thicker wires than specs or they used thinner wires than 16-gauge for their custom 12VHPW cables ? Hmmm. If it's the latter it is disgusting.
Reply
Peksha

Fake news again.
https://d1q3zw97enxzq2.cloudfront.net/images/12vhpwr_vs_12v2x6_xHQcgFn.width-1000.format-webp.webp
Reply
Alvar "Miles" Udell

Or just don't use a third party cable, use the one that comes with your power supply or OEM provided adapter cable. Personally I'd like to see the load balancing adapter that EVGA sold for their cards and use 4-8 pin cables plugged directly into it.
Reply
The Historical Fidelity

hotaru251 said:
so sounds liek a moot point...if the older 12vhp cables were up to standard then they should handle 600w still....if the gpu itself is damaging them then that is STILL a very big issue as means GPU aren't following the standards (as in pulling over that)
Yeah I completely agree, if a cable is built and is advertised as meeting the cable standard…then how are they not able to handle the power delivery the cable standard is rated for.
Reply
AkroZ

The specifications doesn't have much margin of errors, note that 12VHPWR and 12V-2x6 have the same electrical specifications:
They are rated for 9.5A by pin for a total of 684W (9.5 A \00d7 12 V \00d7 6 pin), the specified power is 600W. You only have 14% of safety splitted on 6 pins.
RTX 5090 has a specified power of 575W.

In comparaison 8-pin connectors are rated 8A by pin for a total of 288W (8 A \00d7 12 V \00d7 3 pin) and for a specified power of 150W which means you have a safety margins of 92%. This make it much more reliable.

The issue is in the specifications (proposed by Nvidia): you don't design an electrical connector with this much power with so little safety margin and nearly no safety mechanisms.
They have done that to diminish manufacturing costs. For a standard safety margin this would have needed around 4 times more metal.

Note: you would need 4 connectors 8-pin to power a RTX 5090.
Reply
Conor Stewart

This is just marketing BS and damage control. The cables are exactly the same on both 12VHPWR and 12V 2x6, the only change is to the connector on the GPU and PSU and the only difference is pin length. The cable standards are exactly the same, physically and electrically.

So the only reason the old cables wouldn't be validated for 50 series is if the older cables weren't up to standard, like if they cut corners on the conductor size or the pins used and hoped no one would notice with the lower power draw.

From derbauer's video it looks like this is an issue on the GPU or PSU causing the majority of the current to flow through one or two pairs of conductors, something that would melt a cable even if it was up to spec because something is wrong on the GPU or PSU side and current isn't distributed equally. It is happening with the cables that come with the PSU too.

It is a very strange kind of issue, especially if the pins of the connector are just all connected together on the GPU or PSU side, there shouldn't be much possibility of significant imbalance.
Reply
Moonstick2

Alvar Miles Udell said:
Or just don't use a third party cable, use the one that comes with your power supply or OEM provided adapter cable.
Although bear in mind that the cables that come with the power supply aren't usually made by the PSU manufacturer, even the big names, same as they don't make their own capacitors or wind their own inductors. They get cable manufacturers to make the cables, maybe with a bit of branding. There's no reason to assume that a reputable consumer cable company is making them any worse than a manufacturing company supplying hundreds of thousands of cables to dozens of OEMs where small savings per unit matter. Or that the "third party" cable company isn't getting their cables made by the same manufacturer supplying the OEM.

Conor Stewart said:
So the only reason the old cables wouldn't be validated for 50 series is if the older cables weren't up to standard...
Or if the standard isn't up to scratch.

Lots of people have been slating 12VPWR before all this, especially on matters like the safety margins which by engineering standards are very tight.
Reply
Peksha

https://www.reddit.com/r/pcmasterrace/comments/1io4a67/an_electrical_engineers_take_on_12vhpwr_and/
Reply

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