The noise is not coming from the case, it's coming through the speakers. It's inaudible when only browser, etc running. But when i start games, i hear a spinning up, higher pitched buzzing noise through system sound. It sounds like its frequency is connected to the GPU fan speed.
When i use the motherboards integrated soundcard this phenomena disappears, but i have quality external sound card (Scarlet i2i) and monitor speakers. So i rather use those then my headphones. Also all my PC components are quality.
I was reading some opinion that the Catalyst HDMI audio driver can interfere, but it's not installed.
Windows 10 64bit system.