Jedi95 used a high-end custom water-cooling setup paired with 10 degrees Celsius coolant temperatures to reach a clock speed of 3.33GHz. The only drawback was that the card had to consume nearly 700W.
According to Tom's Hardware the performance achieved by this modified 7900 XTX pushes the card into new territory. In 3DMark Time Spy Extreme, the GPU was able to hit 18,335 points, which exceeds the results of some RTX 4090 cards. For instance, according to PCGamer's RTX 4090 review, it recorded a GPU index score of 16,654 points, which is 10 per cent slower than Jedi95's RX 7900 XTX benchmark result.
This means AMD's RX 7900 XTX can jump a performance tier and compete with Nvidia's flagship RTX 4090 (rather than the RTX 4080) if you are prepared to blow your power bill.
The mod Jedi95 used was a "shunt-like" mod that allows the VRM controller to report false power consumption figures to the GPU, thus bypassing AMD's power limitations. This allowed him to effectively run the 7900 XTX without any power limitations.
According to Jedi95, the mod he used is better than a traditional shunt mod since the power reporting can be controlled with software.