Hey all, now and again, my card vibrates and makes an annoying sound whilst
it does so. Let me be clear he it's the card itself and not the fan.

I believe inductors & capacitors commonly have whine or vibration
issues. On newer cards, you'll see 'solid state chokes' that advertise no
buzzing or vibration. I doubt there's a fix for your problem besides
researching for your next upgrade

rms