In my experience, with my old GTX 970 which suffered from extreme coil whine, it only happened when the GPU was running flat out. For instance, in the menus of certain games, it would be rendering full-speed, pointlessly, at some insane frame rate. As soon as the game started up and the frame rate was limited to something more reasonable, the coil whine would subside.
That makes me wonder if maybe the Vega card isn't being clocked down appropriately, if maybe it's essentially running wide open doing nothing like my 970 would be rendering some stupid loading or menu screen.
The AMD card almost always come with unnecessarily high voltage. e.g. My 7950 factory voltage is 1.094V, and I can turn it down to 0.888V (stay at factory 800/1500MHz) without any problem. And the card can run much cooler with lower fan speed with manaually calibrated voltage.
IMO, AMD just lazy, they give the GPU very high voltage supply to assure stability. However, this unnecessarily high voltage also make the card get into thermal throttling much earlier than required.
When you scroll in a browser etc., the card will jump to a much higher power stage. This action can cause coil whine, or sudden fan spin up. It can be quite annoying.
In Windows, we can use Wattman to fine tune what we want and alleviate the problem. But in MacOS, there is no work around. AFAIK, the Vega card only accept signed ROM. Unlike the old card (e.g. HD7950), we can no longer mod the ROM (voltage, fan profile, etc) and flash the card. So, unless you find a Vega ROM that won’t cause coil whine, and that ROM can fit your card. I don’t think there is any feasible work around in MacOS at this moment.
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