AMD Radeon RX 7900 tests point to potential problems with the vapor chamber design

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

Just one minute into the test, in a horizontal installation, the A and B boards start throttling. A brief analysis revealed that horizontally installed Radeon RX 7900 GPUs ran hotter than vertically installed GPUs. In horizontal mode, these cards ran at speeds “well above” 2000 RPM, as opposed to 1700-1800 RPM in vertical mode. Der8auer created a custom platform to determine whether the lower weight and gravity in horizontal mode are the cause of the higher temperatures. This test produced similar findings to the cooler’s lack of support, indicating that this is not an issue.

The temperature did not decrease after disassembling the cooler and removing the support bracket that is in direct contact with the VRM. The YouTuber assumed that the height of the spacers would have created a small 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 mounts to reduce the distance between the GPU and the cooler, he couldn’t solve the problem.

Another idea involved a problem with the vapor chamber. Since one of the cards examined still worked, Furmark der8auer turned over the entire test bench to determine that the temperature had risen sharply. Even turning the card over did not restore the lowered temperature. Both modified and unmodified RX 7900 reference cards showed an identical problem. This left der8auer with only one possible explanation, a flaw in the vapor chamber design. While not supposed to be rotated, it suggests that the liquid in the chamber is having trouble recirculating after condensation (a vapor chamber is basically a large heat pipe). He believes there may be a flaw in the design or choice of materials, but he is sure it is a problem with the vapor chamber.

Recently, AMD released a brief statement encouraging anyone experiencing thermal throttling to contact customer support. But according to Der8auer, this problem is now affecting a large number of people, and if the vapor chamber is indeed the source of the problem, it could prompt AMD to take drastic action.

Images Credit: Der8auer

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