Question: CPU temperature increases by 8–13°C in fullscreen mode versus windowed.
Question: CPU temperature increases by 8–13°C in fullscreen mode versus windowed.
I observed that my CPU temperature rises significantly when switching to fullscreen mode. It’s considerably lower in windowed or borderless windowed settings, and I’m unsure why. I verified this using both RTSS and HWiNFO to rule out a system issue, but the readings remained consistent.
My machine runs a laptop connected to a 1440p 120Hz external monitor (native 144Hz, adjusted to 120Hz for my FPS goal). The hardware specs are a 3050 Ti with 4GB VRAM and a Ryzen 5 5600H. While not the most powerful configuration, I can achieve around 120FPS in certain games with frame generation at 1080p. I’m using the latest drivers and have updated my operating system, and all games are current.
At another location, I used a 1080p 120Hz monitor, and temperatures stayed normal in both fullscreen and windowed modes. However, with the 1440p display, my CPU temps only increase in fullscreen, while windowed modes remain stable, and the difference is clear.
The screenshots I shared come from First Berserker: Khazan. I also noticed an odd behavior: changing the in-game resolution to 1080p while keeping the desktop at 1440p 120Hz causes my monitor’s refresh rate to drop to 100Hz (but not in borderless mode). This is visible directly on the monitor’s OSD, which displays the current signal resolution and refresh rate.
This issue seems to resolve itself if I set the monitor to its native 144Hz, but even then, when switching the in-game resolution to 1080p, the monitor still shows a 1440p signal at 144Hz. It appears the system is downscaling internally, though the actual output signal remains unchanged.
The CPU temperature spikes exclusively in fullscreen mode. Regardless of resolution or refresh rate settings, fullscreen always runs hotter. Windowed or borderless windowed modes are cooler, but they come with trade-offs like being limited to native resolution or forcing a smaller window. I’m unsure how to fully resolve this.
This problem isn’t limited to Khazan. It also appears in games such as Stellar Blade and Clair Obscur: Expedition 33, where fullscreen mode runs about 10°C hotter than borderless in those titles.
In Stellar Blade, I experience the same refresh rate issue. Switching to 1080p in fullscreen locks me at 100Hz, and I can only reach 120Hz again if I set the monitor to 144Hz. I prefer locking at 120Hz because I think 144Hz can cause frame pacing issues if the game struggles to maintain consistent 144 FPS.
This situation is quite confusing. I would really appreciate any guidance or explanation regarding the temperature increase only in fullscreen and the refresh rate and scaling problems. Thanks ahead of time. It seems like it shouldn’t be an issue, but I’ll include my monitor models just in case. I’m using the Asus TUF VG32V for the 1440p display and an older 1080p 120Hz monitor (the exact model isn’t remembered). I’m using HDMI 2.0 for the Acer and HDMI 2.1 for the Asus. For direct comparison, I can’t test both monitors side by side since they’re in different environments.
Images of Khazan show the CPU temperatures, with higher readings in fullscreen and lower in windowed mode, both at 1080p.
A laptop, please send the make, model and SKU to your laptop. Verify if there are any pending BIOS updates. Additionally, consider checking if you've upgraded the cooling system by replacing the thermal paste and pads with higher-quality materials. You might also want to reinstall a few components on your laptop.