A few months ago, I picked up a Biostar T5XE (CFX-SLI) mainboard.
The first time I installed it (with a mounting kit behind it), I noticed a high-pitched whine coming from it.
I just verified that no other component is emitting the sound (I suspected the power supply or the CPU fan but they're fine, and the hard drives don't do it either- neither does the RAM).
The sound is about 11,000 Hz which dips every so many seconds, and starts when the board is powered on.
Why is it doing this? Is it an internal problem with the board? Is the CPU not making full contact with the board? Or something else entirely?
I've been able to isolate the source of the sound to the motherboard. I used a different PSU, only connecting it to the mainboard. Nothing else was running (except the CPU fan, which I had already tested), and the squealing still persisted.
Also, I know it's not a problem with RAM seating because the squealing persisted after a change.