A common cause of high pitched and loud whine is a sort-of resonance in transformer windings. If so, a new PSU may be in your future.
Thing is, it's easier to diagnose if you hear it rather than read a description. A tranny whine is normally a very pure sort of whine, while DWU's disk screech would be more fingernails down blackboard teeth-aching kind of noise.
That disk screech can be LOUD through. When I started it up in my office, I had complaints from two floors up. Seriously. But it raises the question, how loud is a loud noise? Unpleasant from three feet, or fingers-in-ears from 50 feet? Or whatever.
I had one brand new HD that I took back some years ago because of noise. I told the shop it was noisy, and he said "they all make noise". Not that loud, I told him. After 5 mins of arguing, he got a tech to "take it to our lab and test it." The bloke walked about 75 feet across the store, opened a door, went through and closed it. About a minute later, this god-awful screech, sounding a bit like a whole horde of angry harpies all with beakache, and PMT, started up .... through the closed door. I looked at the sales guy, winked and said "told you it was loud". He said something rude that I can't repeat without banning myself, but was a four letter expletive followed by "me" .... and replaced it.