I did also try PCAT logging with the Radeon RX 7900 XTX during a game engine test, and during a run of Metro Exodus Enhanced Edition at 3440×1440 / Extreme I recorded spikes as high as 421 watts. That is 100 watts higher than the biggest spike we recorded from our RTX 4080 FE, though I will update with PCAT logging on the NVIDIA side as well.
Before leaping to any conclusions about foul play here with an NVIDIA power testing device, please understand that we couldn’t rely on our usual GPU-Z logging. During our testing leading up to this review, GPU-Z was not reporting power draw with these new Radeon cards. The PCAT hardware was a great alternative, as it simply sits between the PCI Express power and slot power and displays the current draw from each.
Finally, a quick note on observed thermals with these reference cards. I don’t have Gamers Nexus-style thermal probes or some other hardware solution, so I’ll have to trust the temps reported by the GPUs. During the looped Metro Exodus benchmark runs I used to record GPU frequencies, the highest GPU core temp was reported as only 67 C, with the GPU hot spot recorded as 79 C (in a very cool 17 – 18 C room). These numbers dropped to 60 C core, 71 C hot spot with the reference 7900 XT in the same test.
There are some problems with this methodology to test thermals, not the least of which is the 90-second duration of the benchmark (though it did run ten times in a row). I only provide this information here because I have the data, but thermals will have to be further explored in a longer duration test.