Added AMD's formal response for manufacturers and distributors, see below...

I have been asked by a number of customers for my thoughts on this because the details have been all over the place, various sites are running tests, and assumptions being made with regard to how systematic of an issue it is.

There is a cooling issue on a small subset of XTX GPUs, the root cause is the vapor chamber itself or perhaps the mating to the primary GPU ASIC, it looks like a small number of units are affected, and AMD is primed to support customers and swap out if necessary.

I have seen approximately 1.5% of the units Bitworks have sold exhibit the issue, it manifests as extremely high temps under a low workload and thermal throttle under even marginal workloads.

Update from AMD

“We are aware that a limited number of users are experiencing unexpected thermal throttling on AMD Radeon RX 7900 XTX graphics cards (reference models made by AMD). Users experiencing unexpected thermal throttling of an AMD Radeon RX 7900 XTX should contact AMD Support(opens in new tab)," stated AMD in a statement to Tom's Hardware.

https://www.amd.com/en/support/contact-call