How fast is AMD's RX 7900 XTX with no power limit? It can match the RTX 4090 GPU

AMD's RDNA 3 flagship GPU can match its Lovelace rival, the RTX 4090, just about, as a new experiment with the Radeon RX 7900 XTX proved - but there are some weighty caveats here.

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The ASUS TUF Radeon RX 7900 XTX can really fly if pushed hard (Image Credit: ASUS)

PC Gamer spotted that an intrepid 7900 XTX owner conducted a test inspired by the question: "What could the 7900 XTX do if AMD didn't handicap it with highly restrictive power limits?"

That person, Jedi95, then detailed the results of juicing up their ASUS TUF Radeon RX 7900 XTX to the max on Reddit, and it makes for very interesting reading.

A mod was applied to remove the graphics card's power limit, with Jedi95 connecting an Elmor Labs EVC2SE to the I2C bus on the board. That enabled the 7900 XTX's power limit to be sidestepped, and the clock speeds were pushed up to 3,467MHz at the fastest levels seen (a startling 3,333MHz on average).

With the GPU cranked up to that pace, the 7900 XTX scored 19,137 for graphics in Time Spy Extreme. PC Gamer points out that this compares to 19,540 for their RTX 4090 Founders Edition, meaning the 7900 XTX with the pedal fully to the metal is only about 2% slower.

That's a negligible difference - in a synthetic benchmark, admittedly - but there are two big catches here. Firstly, the RTX 4090 is running at stock, and could be overclocked to put more distance between it and the AMD flagship.

Secondly, the power usage of the RX 7900 XTX was sky-high in this experiment. We're talking about nearly 700W being pulled, which is clearly pushing way past sensible boundaries.

Running at that kind of wattage is going to be a bad idea for any length of time for obvious reasons - the graphics card wasn't designed for that kind of stress (and it's clear enough why AMD chose to limit the power consumption for the card).

Jedi95 was using a water chiller loop for cooling, too, with the coolant at 10C we're told.

However, the Redditor observes that:

"The stock cooler on the ASUS TUF 7900 XTX is certainly capable of handling a lot more than the 430W limit. It's basically the same size as the cooler on the RTX 4090 Strix, which has a 600W max power limit without modifications."

If you're tempted by all this talk of seriously slick performance levels, and dreaming about what frame rates you might be able to achieve by juicing up your flagship AMD RX 7900 XTX, well, pushing the flagship graphics card is something you'll undertake at your own risk.

Even without any antics around removing power limits, the RX 7900 XTX is still a very impressive GPU, as we made clear in our review of the reference graphics card.