AMD Radeon RX 7900 Testing Suggests Possible Vapor Chamber Design Issues

Der8auer has provided a thorough analysis of the Radeon RX 7900 temperature problem with hot spots. He ordered four cards in order to confirm the most frequently cited issues, such as the differences between horizontal and vertical GPU installation. It turns out that there is a distinction. According to the video, when each card undergoes a 10-minute burn-in test, GPUs mounted vertically will see greater hot spot temperatures. However, this is not the entire story.

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Just one minute into the test, in a horizontal installation, the A and B cards will begin to throttle. A brief analysis revealed that horizontally installed Radeon RX 7900 GPUs ran hotter than those installed vertically. In horizontal mode, these cards ran at speeds “far beyond” 2000 RPM, as opposed to 1700-1800 RPM in vertical mode. Der8auer created a customized platform to determine if the lower weight and gravity reported in horizontal mode are the cause of the higher temperatures. This test yielded comparable findings to the cooler’s lack of support, indicating that this is not a problem.

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The temperature did not decrease after disassembling the cooler and removing the support bracket that is in direct contact with the VRM. The YouTuber presumed that the height of the stand-offs might have created a minor gap that would affect how well the cooler worked. However, this simple test has shown that this is not a problem. Even after grinding the primary cooler’s supports to reduce the distance between the GPU and the cooler, he was unable to resolve the issue.


Another idea involved a vapor chamber issue. As one of the examined cards was still operating, Furmark der8auer turned the entire test bench to determine that the temperature had greatly increased. Even reversing the card did not restore the reduced temperature. Both modified and unmodified RX 7900 reference cards exhibited an identical problem. This left der8auer with only one potential explanation, a flaw in the vapor chamber’s design. Even though it is not supposed to be rotated, it suggests that the liquid within the chamber may have difficulty recirculating after condensing (a vapor chamber is basically a large Heatpipe). He believes that there may be a fault with the design or the choice of materials, but he is certain that this is a vapor chamber issue.

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Recently, AMD issued a brief statement encouraging anybody experiencing thermal throttling to contact customer support. But according to Der8auer, this issue now impacts a large number of people, and if the vapor chamber is indeed the cause of the problem, this might push AMD to take significant action.


Images Credit: Der8auer