I want to shed some additional light on this issue. I too was having lots of static feedback when running UE4. However, I was able to COMPLETELY remove the buzzing by changing the following in my hardware setup.
Original hardware setup:
Headset microphone plugged into front panel on PC Case
Headset audio output plugged into Komplete Audio 6 (USB Audio Box) Phones Output
New hardware setup:
Headset microphone and audio output plugged into front panel of PC Case.
Summary: It appears that if you’re routing your microphone and audio through two separate interfaces (front panel, USB AI/O, etc) it will likely pickup the sonic resonance of the GPU. However, when both input and output devices are plugged into the same interface, the audio disappears.
It would be nice to confirm it this works for any other uses.