Asus' "Equalizer" cable for 12V2x6 with questionable benefit

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First samples of a cable called “Asus ROG Equalizer” are currently landing with hardware testers. This is a variant of a cable with 12V2x6 connectors for connecting power supplies and graphics cards. This small connector and its predecessor 12VHPWR have been disreputable for years because they overheat easily. As a result, there have been numerous cases of melted connectors and defects in both power supplies and graphics cards. Initially, device manufacturers often dismissed these as “user error,” allegedly caused by poorly inserted connectors or excessively bent cables. However, with the RTX 5090 at the latest, it became clear that the connection is inherently problematic when it has to operate with the 575 watts or more required for this card.

For some time now, there have been cables and monitoring devices for the connections that are intended to alleviate the weak points. Asus' sub-brand ROG now offers the “Equalizer,” which can also be translated as “stabilizer.” It is a unidirectional 12V2x6 cable with some special features: on the graphics card side, the +12-volt lines and ground connections are bridged, there are two proprietary measuring lines for the voltages, and gold-plated contacts. In addition, according to Asus, the springs in the connectors are said to be particularly contact-friendly.

The Equalizer bridges – but that doesn't help

Asus' marketing doesn't skimp on big numbers either. Instead of the 9.2 amperes per conductor and connector previously specified for the connection, each of the six 12-volt connections is supposed to withstand a full 17 amperes. That would be a full 204 watts over each individual conductor – no one has yet tried to see if the connectors can handle that.

After a theoretical consideration and measurement of the different currents across the conductors, hardware developer and YouTuber Roman “8auer” Hartung has since disassembled the cable.

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It turned out that clips on the graphics card side actually bridge the six lines each for +12 volts and ground. This is otherwise done on many models on the graphics card itself and is a significant part of the problem: if one of the connections, for example in the connector, has a particularly high resistance and thus a voltage drop, the others compensate for it. This can lead to very different currents flowing through the conductors and overloading individual ones.

Where the lines are electrically merged doesn't matter. The idea of bridging them before the card is not new per se: Nvidia's included adapters from multiple PCIe 8-pin connectors to 12V2x6 also bridge the lines before the graphics card.

Roman Hartung measured a deviation of up to 3.6 amperes between the lines with an RTX 5090 under the extreme load of the “Furmark” program with the Equalizer's intact bridge. This occurred with one of the three tested cables. The best Equalizer cable achieved a 2.0 ampere difference, another Asus cable without a bridge only 0.6 amperes. When the tester removed the bridge on an Equalizer cable in his second video, only 1.5 ampere differences resulted.

No active load balancing

The Equalizer, contrary to its name, cannot actively balance these different currents. Although there is a proprietary connection on the power supply side called “Intelligent Voltage Stabilizer” (IVS) by Asus. It only fits Asus power supplies and represents a kind of return channel for ground and +12 volts as they arrive at the graphics card. But only for the bridged sum, not for each individual conductor. Only the graphics card itself could measure what actually lands on each conductor, i.e., with all resistances up to that point.

Asus also refers to IVS only as part of its “GPU First” technology, which is intended to prioritize the power supply's 12-volt supply for the graphics card. It is therefore a regulation in the power supply. There is no active load balancing for each individual line to the card.

Roman Hartung also examined the last component of the Equalizer: the supposedly novel spring connections in the connector, which are also gold-plated. However, according to his surface area estimates under the electron microscope, they did not offer any significant advantage over other connector types. The actual contact surfaces in the connector are only 0.2 to 0.4 square millimeters in size – but there are several of them in each connector for each of these connections.

Gold on the contact surface can also be counterproductive, as most 12V2x6 connections, including those on graphics cards, are tinned and not gold-plated. The abrasion of the tin can be another source of increased resistance.

With all this, Hartung's conclusion on the Asus Equalizer in the video is also: “I don't see the added value.” The Asus cable is available for around 50 euros (starting from 49,90 €), and in the future, it will be included with some of the manufacturer's power supplies.

12V2x6 remains the actual problem

The current findings once again suggest that the design of the 12V2x6 connector and its tiny form factor are the problem – not the cables, not power supplies and graphics cards, or even clumsy users. Even with repeated insertion of the same parts, you cannot know exactly which pin has good contact and how good it is. And without monitoring the currents and voltages on both sides and for each individual conductor separately, no circuit can compensate for any overload of a conductor. Sending so much power and thus high currents through tiny plug contacts once again appears to be a rather bad idea.

(nie)