if it a fan issue or just a fan..you can see if it the gpu fan buy using msi afterburner and turning the gpu fan up. most people going to say is get a ppaler town tun and see if you can pin point it that way. I would check to see if you have active or passive cooling on your power supply. if it passive it might be the power supply fan your hearing when it spins up. hardware monitor will help you see if it a temp issue with your pc or a voltage issue with your power supply.
I've had this issue a number of times over the years. The last time I really noticed it was with my old gigabyte skt1156 board. In some games' loading screens it was unbearable.
I've since upgraded to all my kit, from mobo and cpu to gfx card and psu. I still notice a slight noise sometimes, but it's nowhere near as bad.
I too went through all my kit at the time, thinking it was the PSU. I changed that first, no difference, then I upgraded my GFX card, still no change. In the end it was replacing the mobo (and cpu, but I don't think that was at issue) that fixed it for me.
And so you know, it sounded just like your second vid.
I'm not sure. I had no end of issues with that old board. My rig would hard reset without warning in some games, and BSOD or lock up in others.
I wasn't to happy about the shutting down malarkey (repeatedly hard resetting the machine whilst it's running can never be a good thing), so that was the reason for replacing it.
I would say that it's probably okay for now, but if you start to notice more and more errors, the machine resetting itself a lot etc., then it might be prudent to look at upgrading/replacing some parts. I can only go off my experience here, so for me, I'd be looking at the mobo first.
The thing is this computer is only about 2 weeks old. I've only heard the noise about 3-4 instances during that time. System runs totally beautifully otherwise, was just wanting to make sure that noise wasn't anything damaging. From I can deduce from online documents on the matter is it's just an annoyance, just wanting to make sure though.