When I probe the bucks to find out which mosfet is which for MB reviews, it was always whatever voltage I had set it to or auto. Never seen it go to 1.5V for SoC
But I also only had DDR5-6000 2x16 in at the time and R23 load though, so I can see like 64GB or 6400 doing weird stuff or idle. Checked my CPU yesterday, no burn marks yet
Having read more of the findings, it's limited to various boards, especially on older BIOSes.
I'll keep editing this post instead of making new ones as it's related to high speed RAM, but by the time anyone buys more DDR5 RAM there will be updates to fix this to install and be able to use the ram safely.
"As soon as EXPO is enabled, the CPU SOC and CPU VDDIO/MC voltages increase to 1.36-1.4v, sometimes boosting to 1.5V in Windows, causing instant death on the X3D"
(Quoted from another TPU user who quoted someone else etc)
And then some boards have safeties disabled when PBO is enabled by using "motherboard defaults", so enabling PBO to access curve optimiser -
which RAM reviews wouldnt use - would unlock all the amperages and wattages, and disable temperature based safeties too. Those "motherboard defaults" are basically "infinity"
Then theres a genuine bug that may be AMD related, where sleep or hibernate is triggering issues with temperature detection and fan speeds - which may be semi-related, or just a coincidence (confirmed on MSI boards)
Seems like the issues vary between the motherboard brands, but AMD is expected to provide a safety net for them in new AGESA.
DDR5 Expo voltages being cloned to VSOC has been reported on Asus and Gibabyte boards so far, so yeah definitely keep an eye out on your review system(s)
Edit: Asus was automatically setting SoC 1.35v when EXPO was enabled, but over time was creeping up higher over time to 1.5v as the CPU aged - the longer it ran at higher voltages, the less resistance the CPU had internally and the more power went through.
Edit 2: Asus boards have an insanely high OCP (overcurrent protection) effectively infinite.
TL;DR: You'd get a crash or hang, the system would try and reboot (the famous ryzen slow boot bug) and just keep
feeding more and more power until the system powered on, or exploded