I replaced my Gigabyte B650M D3HP motherboard with an Asus ROG STRIX B850-A Gaming WiFi. With the previous board, my Ryzen 5 9600X usually idled around 40°C. The day I installed the new board, the temperature was still about 40°C, but since then it has stayed closer to 47°C and rarely drops below that. The CPU is running without PBO or manual overclocking and typically operates around 5.2 GHz. I reused the same Arctic MX-6 thermal paste and DeepCool AK620 Digital Pro cooler. I'm not concerned about 47°C itself, but I'm curious what could explain the increase. Could the new motherboard be using different power-management settings or a different default fan curve?
2 Answers
Idle temperature is affected by more than the cooler and thermal paste. Check whether the BIOS enabled different default settings, including a more aggressive boost behavior, higher SOC or core voltage, and a quieter CPU-fan curve. Also compare temperatures under the same Windows power plan and with the same background programs running. A difference of 7°C between two boards can be normal and does not necessarily indicate a mounting or paste problem.
The most likely explanation is a difference in the motherboard's default fan curve or power-management behavior. A newer board may allow slightly higher idle voltage, keep background boost activity going, or run the fans more quietly before increasing their speed. That can easily produce a several-degree difference at idle. As long as load temperatures remain reasonable—roughly below the mid-80s Celsius—and performance is normal, 47°C at idle is not a problem.
That makes sense. I’m not worried about the temperature itself; I mainly wanted to know whether the change could be caused by how the new board manages power.