I'm running Fedora 44 with KDE Plasma and comparing its temperatures with the same hardware on Windows 11. I configured LACT and CoolerControl, making sure CoolerControl does not manage the GPU, and used very similar fan curves in both systems. I also applied the same undervolt to my Radeon 9070. On Fedora, I'm seeing about 45°C hotspot, 40°C GPU temperature, and 43°C CPU temperature. On Windows 11, the temperatures are usually around 29°C hotspot, 28°C GPU, and 38°C CPU, sometimes a couple of degrees lower. Both systems are set to balanced power mode. What could explain the difference?
3 Answers
The temperature difference could also come from how each operating system handles GPU power management and display compositing. KDE’s desktop effects, refresh-rate handling, or a GPU that is not reaching its lowest idle state can add a little heat. Check whether the GPU is staying at a higher memory or core clock, especially with multiple monitors or high-refresh displays.
Windows may be putting the CPU and GPU into lower-power states more aggressively when the system is idle. Even if both systems are set to balanced mode, their boost, clock, voltage, and idle-power behavior can differ. Check the actual GPU and CPU clocks, package power, and utilization while idle rather than comparing only the fan curves.
The claim that KDE itself is automatically responsible is too broad. Plasma can use more resources than a very minimal desktop, but a 10–15°C difference is more likely related to power states, clock behavior, background activity, or the way temperatures are being reported. Comparing idle wattage and clocks should help identify the cause.
Would switching from KDE Plasma to GNOME make a noticeable difference, or should I investigate the GPU and power settings first?

Both systems are set to balanced, if that’s the setting you mean. I’ll compare idle clocks and power draw as well.