Question I can't figure out if it's PSU coil whine during PC shutdown ?

[runningw]

I recently built a new PC with Thermaltake GF3 1000W PSU. The problem is that during the shutdown process I can hear whine from the PSU. It is not loud, but since the pitch is high, it is very easy to hear. I tried to switch out this PSU with my old one, and the whine disappeared. I also tried to pair this new PSU with my old system, and my old system did not produce such whine during shutting down. Afterwards, I contacted Thermaltake and they send me a new PSU, but unfortunately it has the same problem. I am in the process of returning the PSU. I wonder why whine only occurs when this PSU is paired with my new system. What could be the root cause? I have a video (https://gumlet.tv/watch/67cd11e23ae6ee3ff9c333d4) to show the problem (might need to turn up the volume).

PC Components are as follows.
PCPartPicker Part List

CPU: AMD Ryzen 7 9800X3D 4.7 GHz 8-Core Processor
CPU Cooler: Deepcool LT720 85.85 CFM Liquid CPU Cooler
Motherboard: MSI MAG X870 TOMAHAWK WIFI ATX AM5 Motherboard
Memory: Corsair Dominator Titanium 32 GB (2 x 16 GB) DDR5-6000 CL30 Memory
Storage: Samsung 990 EVO Plus 2 TB M.2-2280 PCIe 5.0 X2 NVME Solid State Drive ($129.99 @ Abt)
Storage: Western Digital WD_BLACK 2 TB 3.5" 7200 RPM Internal Hard Drive
Video Card: Asus TUF GAMING OC GeForce RTX 4070 Ti SUPER 16 GB Video Card
Case: Silverstone SETA D1 ATX Mid Tower Case
Power Supply: Thermaltake Toughpower GF3 TT Premium 1000 W 80+ Gold Certified Fully Modular ATX Power Supply
Optical Drive: Asus DRW-24D5MT DVD/CD Writer
Total: $129.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2025-03-08 22:15 EST-0500

 

[Lutfij]

I also tried to pair this new PSU with my old system, and my old system did not produce such whine during shutting down.
For the sake of relevance, what are the specs to your old system?

Are you sure the noise isn't from the fan from the PSU? You should roll up a sheet of A4 paper into a cylinder, hold one end up to your ear and then use the other end to probe for the source the sound. You will need to take both side panels off the case in order to inspect for the culprit producing said sound.

Does the sound disappear when you remove the discrete GPU from your build, working with only the iGPU?