When the Radeon RX 7900 XTX launched, some gamers were disappointed it wasn’t the rumored fire-breathing GPU. Nvidia certainly anticipated something beastly and ended up overshooting the target with the RTX 4090, quickly crowned the world’s most powerful GPU. Not long after that one-sided battle, AMD crowed it could have made a card to compete with the 4090 if it wanted to, but it said it was not very practical. Now an intrepid modder has decided to test AMD’s claims by removing all power limits from a 7900 XTX card, and it turns out AMD wasn’t kidding. It made a 4090 challenger, but only when given almost 700W of power.
This intriguing experiment was conducted by a member of the /r/AMD subreddit, who used a hardware mod that allows you to remove GPU voltage limitations. Redditor jedi95 wrote that the effort was to find the answer to the question, “What could the 7900 XTX do if AMD didn’t handicap it with highly restrictive power limits?”
To find out, they employed an Elmor Labs EVC2SE to control the GPU’s voltage manually. The Redditor notes the card used—an Asus TUF Radeon RX 7900 XTX—has a header on the PCB for this modification. They connected the card to their custom liquid loop using an EK Quantum Vector full-coverage water block, keeping coolant temps in check with a chiller device.
The tests were performed on an open test bench with an EK Quantum Vector custom loop cooler.
Credit: /u/jedi95 on Reddit
The benchmark results show that the Radeon RX 7900 XTX can be a formidable GPU when it’s unshackled from power constraints. Its clock speeds got a massive boost, with the card averaging 3,333MHz compared with the 2,300MHz stock “game clock.” The maximum clock recorded was 3,467MHz, so almost a gigahertz more than the max boost clock of 2,500MHz. This required a ton of power, though, with the card soaking up 696W at its peak.
The result is an undeniable beast of a GPU. It was neck-and-neck with an RTX 4090 in Time Spy Extreme at 19,137, compared with an RTX 4090’s score of 19,508, according to TechSpot. For reference, an RTX 4080 can hit 11,000 in this test, so the Radeon completely smokes it. They also ran Cyberpunk at 1440p with Ultra settings and ray tracing at 49fps without FSR enabled, which is a 16% gain over the stock card.
If you’re wondering what the GPU temps were, so were we. It turns out they’re pretty good, thanks to the lavish cooling setup. Jedi95 states they’re using a “chiller” setup to keep the coolant chilly, with a target temp of 21C. Overall they said in testing, the GPU die’s edge temp was just 23C, with the hotspot hitting 63C. It would seem for an experiment with these clock speeds, exotic cooling is mandatory.