My PC is making an annoying whine which I have self-diagnosed as coil whine because it seems to be coming from the power supply. This picture shows the rear of my PC, with some annotations.
I have found that if I hold a pack of post-it notes (or something of equivalent thickness) over the top vent marked with red, the noise cannot be heard. I am concerned though that doing so will possibly cause overheating; at least from what I've read elsewhere it could do.
My question is, given the presence of the "secondary" vent marked in blue, would this supply adequate air flow that the PSU fan could use to keep the PSU cool?
(I don't know enough about modern hardware components and - specifically - air flows, so am hoping that someone here does and can provide a reasoned answer)
Follow up question after answer accepted here: Safe method of blocking whining noise from PSU exhaust?