According to a video by Gamers Nexus, AMD’s reference RX 7900 XTX features a unique ambient thermal sensor that allows the GPU to measure the air-inlet temperature coming directly into the cooler. We don’t know why AMD added this sensor to its cards, but it has the potential to be very useful.
Having an ambient temperature sensor inside your GPU cooler has several advantages. Gamer Nexus notes that one of the most notable benefits is monitoring the ambient temperature when the fan is off (0db mode), protecting the PCB components on the card from overheating.
Gamer Nexus continues, this exact issue was a problem with EVGA’s GTX 10 series graphics cards before the ICX cooler was introduced. The card’s 0db mode accidentally overheats some power delivery components and dies prematurely. As a result, EVGA recalled those cards and eventually replaced them with ICX coolers featuring additional thermal sensors
However, it’s worth noting that this was a one-time ordeal, and almost every card on the market today has a zero RPM fan mode, with coolers designed to take advantage of that feature.
In the case of the 7900 XTX, AMD probably added this sensor as an extra safety measure, just in case some PCB components get too hot while the GPU core is still cool enough to keep the fans off. Once the temperature gets too hot, the card can initiate a secondary fan curve to keep the PCB components cool while running the fan at a very low RPM.
Hopefully, AMD will provide end-users access to this sensor inside the Adrenaline control panel (and 3rd party applications) as it can be helpful in a variety of situations – not just for keeping the card cool. For example, the ambient sensor can also be used to measure the actual ambient temperature inside the entire system to monitor and troubleshoot high temperatures in other components and/or chassis fans.
Unfortunately, AMD neglected to share why it added this sensor to its reference card, leaving us to guess. But if we get an official comment from AMD, we will update you here with the details.