AMD’s Radeon RX 7900 XTX (reference model) graphics cards may be shipping with a faulty heatsink, resulting in thermal throttling and overheating. As reported earlier, these GPUs hit temperatures as high as 110C under load, leading to severe clock fluctuation and reduced sustained performance. While all the RDNA 3 cards run hot, the reference design runs into its TJ max limit under load.
Well-known overclocker “der8aer” has been investigating the Radeon RX 7900 XTX for possible flaws or defects and may have found something. Previously, he demonstrated that merely reseating the heatsink and replacing the thermal paste knocked several degrees off the chart. Using four reference cards, he has now uncovered what seems to be a defective vapor chamber.
To begin with, the orientation of the graphics card affects the thermals way more than it should. When horizontal, the RX 7900 XTX runs an entire 15-20C cooler. And yet, the GPU throttles under the burn-in test. As you’d expect, turning the card to a vertical setup results in a sharp increase in temperature, which, surprisingly, wasn’t undone by turning it back to its horizontal position.
These findings indicate that the vapor chamber that forms the heart of the heatsink isn’t functioning as intended. The coolant in the chamber cannot circulate properly after condensation, leading to overheating during prolonged testing. It could also be a low-quality coolant or an inadequate quantity. Either way, the Radeon RX 7900 XTX reference card running into 110C isn’t “by design” and needs to be fixed.
Source: YouTube (de8auer)
