So my Corsair RM1000i has, AFAIK, Started to develop coil whine, Only started around 1 month ago, Not noticeable during the day but when it gets quiet at night any movement with the mouse, Scrolling pages etc... and I can hear it albeit very faintly, I thought it was the GPU at first so I unplugged my 1080 Ti and used the 9900K's iGPU, Same exact sound. This is what it sounds like, Amplified a little to make it more obvious, Sounds like a tiny cricket or grass hopper even when just sat at the desktop doing nothing but moving the mouse cursor, If there is zero onscreen activity there is no sound but even on the iGPU as soon as there is any onscreen activity I hear it. Cause for concern ?
If you haven't cleaned it yet, take the grill off and apply some compressed air. DO NOT take any other screws off, as it might void warranty.
Have you tried tapping the fan, if its spinning ? Otherwise, i'd go with Sverek's suggestion of putting some compressed air through there when its switched off. Careful to not break any fan blades. I'd try and hold a vacuum cleaner to the PSU exhaust when you blow air through it from the fan side.
Are you sure the sound is coming from the PSU? I have heard many systems with sounds as you describe coming from the speakers when the mouse moves. If it is from the PSU, it isnt cause for concern, it is most likely coil whine as you surmised. Should it annoy you enough, contact Corsair who will likely issue an RMA.
