That occurred to me when the murderboard thing started getting press visibility back in March. If there was a simple answer probably it would have been found in the past nine months. While the r/ASRock anecdata everybody’s working from doesn’t seem to include workloads or GPUs, it seems plausible to me correlations might exist with those the way they do with the 9800X3D, certain lot codes, use of PBO, and 1.4 V DDR kits. Since GPUs tend to pull more power than AM5 CPUs, GPU intensive workloads are likely the most influential ones on PSU activity.
It’s entirely speculative but perhaps workload and GPU combinations are one reason why time to failure seems to vary widely. Unlikely there’ll ever be sufficient data to test hypothesis around game or GPGPU power levels, though, much less things like use of Furmark for GPU acceptance testing and thermal evaluation.
One thing about RDNA4 is, based on the small numbers of cards Igor’s has reported measurements for, it appears AMD’s card designs return ~90% of ground current via the PCIe slot rather than Nvidia’s ~65%. So a 9070 XT is capable to put ~270-330 W worth of current through EPS and the 24-pin, comparable to a 4090 or 5080. If the deaths result from voltage, and are thus linked to ground potentials, then 9070 XTs would be the most cost effective way of getting into ground problems.
In particular, the PEG-EPS return path runs along the CPU VRMs. So if the VRM ground references aren’t resilient to GPU current flows the CPU’ll get hit. Also the lowest impedance PEG-24-pin path probably runs under the DDR sockets, which is maybe kind of interesting given the possible correlation with 1.4 V kits. The resulting current distribution’s influenced by the motherboard but might be more a function of PSU cabling and PSU internal layout.
Another question I have here is why MSI started placing auxiliary 8-pin power connectors on their boards. It puts probably five ground pins a bit closer to PEG than the eight EPS pins and makes a triangle with the eight 24-pin grounds. That’s not insignificant to changing a motherboard’s ground balance.
Could also be a manifestation of the tendency to hit stability problems around idle state voltage transitions. Like maybe if there’s degradation while active and then it’s an idle transition which finally makes something blow for good.