Benchmarks: Temperature
Heat build-up is the enemy of all passively-cooled PCs. Nofan A890S is no exception, and when performing a 4K video transcode using Handbrake the CPU hit 90ºC within two minutes.
The Intel chip didn't throttle, and we encountered no sign of instability, yet having become accustomed to air or liquid coolers, we didn't feel entirely comfortable with an expensive Core i7-8700K getting so hot under the collar. However, in response to our concern, Quiet PC has categorically stated that in five years of building totally fanless PCs "we have not experienced any issues in terms of inadequate CPU cooling, provided the maximum TDP of the CPU does not exceed the limitation of the CPU cooler."