The vapor chamber on AMD's Radeon RX 7900 XTX graphics card has finally been dissected by Der8auer who's trying to figure out the overheating issues.
AMD Radeon RX 7900 XTX Vapor Chamber Dissected, Investigation Points Out To Low Fluid Levels As A Potential Cause of Overheating
Der8auer has been hard at work ever to unearth the root cause of the overheating issues that have affected the Radeon RX 7900 XTX reference graphics cards. Ever since we first reported it, there are several possible findings made by experts including Der8auer and Igor's Lab. There have now been multiple cases reported and the issue isn't something that AMD can overlook and decline RMAs for.
During the dissection of the vapor chamber on the AMD Radeon RX 7900 XTX reference model, the cooler shows no material and design defects and is actually well-built with a very large surface area that it covers. Also, the vapor chamber did have liquid within it although the particular RX 7900 XTX cards that were CNC-drilled by Der8auer were units that were affected with the overheating issues.
So it is very likely that while there's definitely fluid within the vapor chamber, the amount of fluid is not enough on a certain batch. And by certain batches, I believe that not all reference AMD Radeon RX 7900 XTX cards might be affected by this since, in various polls (via Computerbase), only a quarter of the users are facing this issue. Igor Wallossek of Igor's Lab also pointed out the same in his findings and he even managed to quote a manufacturer who suspects that the fluid level within a certain batch could've not met the spec
First feedback from a manufacturer: they suspect that too little liquid was introduced in at least one batch. Which could also explain the position dependency. Hanging horizontally, the condensate would then no longer come up.
If this is indeed a small batch, then AMD can definitely open up an RMA channel and send affected users with a replacement unit (however one user was declined a replacement due to lower stock quantities). This is still a serious issue that AMD should address and now that they have some input from the community on the issue, they should start working on a resolution as soon as possible.