Overclocking

Overclocking the Radeon RX 7900 XTX is complicated. Just like on RDNA2, you can no longer dial in a specific clock frequency, but you're operating with min/max sliders to set a range. Surprisingly, changing the GPU clock either does nothing for performance, or it results in a loss of performance or crashes the card when set too high. I haven't been able to find any setting that actually increases performance.

It's great to see that AMD has unlocked the slider length (in the past you often ran out of slider length, effectively capping the OC potential).

Memory overclocking works well, but you have to monitor performance. Once memory becomes unstable, there will be no visual corruption, but performance goes down.

I found the best gains for overclocking in general can be found when setting the power limit to maximum (+15%) and combining that with an undervolt that reduces heat output and GPU temperature considerably, which lets the boost algorithm boost higher, for longer.

With OC, without undervolt, you'll often get the fans spinning at 100%, because the Hot Spot temperature reaches around 100°C.

Overclocked Performance

Using these clock frequencies, we ran a quick test of Unigine Heaven to evaluate the gains from overclocking.


Actual 3D performance gained from overclocking is 0.9% / 1.2% / 6.8%.

In the future we'll replace Unigine Heaven for OC testing with a more modern benchmark that scales better.