A Reddit user known as Jedi95 recently performed a modification on the AMD RX 7900 XTX, one of the top-performing GPUs, in order to eliminate the power limit and test its maximum potential. By utilizing a high-end custom water-cooling setup with extremely low coolant temperatures of around 10 degrees Celsius, Jedi95 achieved impressive results.
The power-modded AMD RX 7900 XTX reached an astonishing clock speed of 3.33GHz and demonstrated performance comparable to that of the RTX 4090 in 3DMark benchmarks. However, achieving such performance required the card to consume nearly 700W of power.
The performance achieved through the modified AMD RX 7900 XTX exceeded expectations and even surpassed some RTX 4090 cards in the 3DMark Time Spy Extreme test, scoring 18,335 points compared to the RTX 4090’s GPU index score of 16,654 points, as reported in PCGamer’s review.
This suggests that AMD RX 7900 XTX has the potential to compete with Nvidia’s flagship RTX 4090, surpassing the performance of the RTX 4080, albeit at the cost of significantly higher power consumption. It’s important to note that 3DMark benchmarks may not necessarily reflect real-world gaming performance.
Power throttling is a common occurrence with AMD’s RX 7900-series GPUs, as most games can push these GPUs to their maximum power rating, resulting in throttling or reduced clock speeds. This differs from Nvidia’s RTX 40-series GPUs, which often operate below their maximum power consumption during gaming.
Jedi95’s modified AMD RX 7900 XTX also matched the best benchmark results of the GPU in the 3DMark browser, even when compared to GPUs likely cooled with liquid nitrogen.
The modification performed by Jedi95 involved a “shunt-like” mod that manipulated the VRM controller to report false power consumption figures to the GPU, effectively bypassing AMD’s power limitations.
This allowed the AMD RX 7900 XTX to operate without any power restrictions, as the GPU remained unaware of its actual power consumption. Jedi95 stated that this mod was superior to a traditional shunt mod, as power reporting could be controlled using software.
It’s not surprising that pushing voltage and frequency beyond the chip’s designed limits significantly increases power consumption. Most chips, including CPUs, GPUs, and other system-on-chips (SOCs), are optimized for specific voltage and frequency ranges.
These findings offer insights into the potential performance capabilities of AMD’s RDNA 3 GPUs when power limits are removed. The Navi 31 chip used in the AMD RX 7900 XTX can achieve incredibly high clock speeds well above 3.3GHz, resulting in significantly improved performance.
Based on Jedi95’s results, it appears that AMD has significant headroom to create a theoretical RX 7950 XTX that could rival the RTX 4090. However, achieving such performance would require AMD to significantly increase the chip’s power consumption.
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