Consider switching to an all-in-one cooler for your AMD 5900x with Noctua NH-D15.
Consider switching to an all-in-one cooler for your AMD 5900x with Noctua NH-D15.
Your heating problems might stem from the 3080 unit. It captures air, warms it, and sends it to the CPU cooler. Try setting the 3080 fans to full speed and then run your CPU stress test. If temperatures drop afterward, the GPU is likely the issue. For AIO coolers I opt for EK 360mm, which offers roughly 5°C better cooling than a NH-D15, EVGA 360mm, and Silverstone 360mm. Here are my R20 bench results using a 5900x at stock.