So I've been running an Asus Direct Cu II R9 290x for a while now and have finally gotten fed up with an intermittent high pitched that I believe is coming from it. It generally only starts after the GPU has been running for a while or gaming for a while but then continues to make noise even when the GPU is at idle. It's a very high pitched steady noise right at the threshold where a lot of people couldn't hear it, which makes me think it's not coil whine as the coil whine the GPU makes in game menus(400-800+ fps) sounds completely different and is much lower pitched.
I'd like to determine whether it's the fans making the noise or if it's coil whine, but to do so I'd need to stop the fans and see if the noise persists. So to get to the point what's the best way to stop GPU fans and not cause damage to the system?