ASUS ROG Astral GeForce RTX 5090 with shunt mod unleashes higher 800W power limit

ASUS's flagship ROG Astral GeForce RTX 5090 graphics card has been shunt-modded by professional overclocker Der8auer, pushing its power limit to a much higher 800W with some interesting results.

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The liquid-cooled ASUS ROG Astral RTX 5090 is a beast on its own with a larger 2.5-slot thermal solution, with a 360mm AIO cooler and three fans, as well as the fan on the graphics card itself. In its stock form, the ASUS ROG Astral RTX 5090 has a 600W power limit and can't be changed through software, with the card designed to be fed 600W.

The 12V-2x6 power connector on the ASUS ROG Astral RTX 5090 is designed for 600W of power flowing into it, but that's not the maximum that the cable can handle. This is where Roman "Der8auer" Hartung steps in, shunt-modding the card and allowing a higher 800W power limit.

Der8auer has shown the results of what can happen if increased current flows through one of the six 12V power cables, which can result in the connector melting. The overclocker pushed the ASUS ROG Astral RTX 5090 with the shunt mod for a short overclocking session, to see what it could do.

The overclocker performed some testing on the card without the mods, with the ASUS ROG Astral RTX 5090 running somewhere between 2800MHz and 2820MHz during 3DMark Speed Way runs, while hitting a maximum temperature of 60C. The card easily hits its maximum power limit of 600W pretty easily, which is where the shunt-modding comes into play.

Shunt-modding requires physical modification to the PCB itself, where you have to replace, bypassing or adding more resistors to existing shunt resistors. Der8auer added 5 milliohm resistors in parallel to the 2 milliohm, which reduces the resistance to 1.4 milliohm, with the overclocker explaining that this tricks the power management circuit to see 30% lower power consumption.

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Just performing this modification without additional changes, increases the power limit from 580-600W, all the way up to 650-720W. Der8auer tweaked the card through ASUS's in-house GPU Tweak software, increasing the voltage flowing into the card up to a much higher 750W-786W. This also makes room for higher GPU clock speeds, somewhere between 100-200MHz higher than stock, with manual overclocking to both the GPU and GDDR7 memory, passing 800W for the first time ever.

With the additional power flowing into the ASUS ROG Astral RTX 5090, Der8auer said that the graphics card can now pass the RTX PRO 6000 Blackwell workstation GPU, which has more GPU cores, a far larger 96GB of GDDR7 (up from the 32GB on the RTX 5090), and a similar power limit to the ROG Astral RTX 5090. With the additional 200W of power flowing into the shunt-modded ROG Astral RTX 5090 makes all the difference with its increased GPU clocks.

Der8auer explains: "that's also why I thought it's ideal to test shunt modding with this card, because it's just constantly running at the 600W power target. And even if we want to do overclocking, you can't really get more performance out of it because you can't really increase the GPU clock of memory clock further".