Another AMD AM5 CPU has reportedly swelled and died, this time a Ryzen 9 9900X less than a year old

Another AMD AM5 processor has reportedly failed with a visible physical deformation, this time a Ryzen 9 9900X. Reddit user TheImmigrantEngineer posted about the incident, describing how their PC suddenly stopped working, with a Code 00 error displayed, and the red CPU debug LED visible on an MSI MAG X870E Tomahawk WiFi motherboard.

After removing the cooler and CPU to investigate, the owner found a small physical bump on the underside of the processor near the center of the contact pad area. The integrated heat spreader showed no visible damage, and the thermal paste spread appeared normal. The damage was between the silicon and the substrate beneath it, invisible from the outside until the chip was removed.

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The system was less than a year old and was running a Corsair RM1000X power supply and a 240mm DeepCool AIO cooler. The PSU was tested in another system without issues, ruling it out as the cause. No manual overclocking or voltage tuning was applied, though Precision Boost Overdrive was enabled in the BIOS, meaning the system was not running a fully stock configuration. The BIOS in use was from early 2026 and was flashed sometime between late January and early February, which rules out any early AM5 launch BIOS issues as a contributing factor.

This is not the first time we've seen this kind of physical deformation on an AM5 processor. A similar case was recently reported involving a Ryzen 9 7950X3D, where a Reddit user spotted visible swelling on the back of the CPU substrate. The motherboard and power supply were both cleared after testing, and no definitive root cause was identified.

In that earlier case, AMD initially rejected the warranty claim before reversing its decision following public attention. The Ryzen 9 9900X owner has indicated they plan to pursue an RMA, so it will be interesting to see how AMD handles this case given that precedent.