Sound card emitting EMI/buzzy interference, physically and in-game/in-voice

I have a Xonar DX which was working fine until I upgraded my computer this week. New everything. Now, whenever the GPU is in heavy use (e.g. in-game), I get a buzzing noise, both physically from the sound card (I think? or somewhere from the pc) as well as some buzzing coming through my microphone - friends are complaining about it. Like if I alt-tab to windows, it almost disappears (doesn't fully go away) but I'll alt-tab back to the game, and it's there again.

It seems to be a pretty common issue, and I've been led to believe that it's a case of modern GPUs causing interference (see here for more info)

I'm actually really upset as my glorious new build was great otherwise.

What's the best solution here? If there was an easy fix, I'd love to know, as audio-quality wise it's a wonderful sound card and i'd like to keep it. But it seems like I'm going to be forced onto using on-board sound? Or should I get a DAC? Though with a DAC, there's no microphone input right? I mean I could get a different soundcard, but I'm worried they will all have this issue, unless there's one with good EMI shielding - maybe even that won't solve it.

What does everyone use for good audio with mic here?