weird sound after shutting down pc

[hwsinn]

After shutting down the pc, my pc will have this high frequency sound. I am not sure which component is emitting that sound but when i turn off the power supply it will be gone

Im running on Gigabyte Z87X-UD3H and using a seasonic X750

 

[jtjt00]

Maybe the seasonic psu.

 

[hwsinn]

did abit of testing.
Power cable all in. Disconnected every modular cable one by one. PCIe, CPU, Sata etc. Only left motherboard cable left. Sound was there.
Disconnected MB cable and sound was gone. So most likely MB.

Can i seek the bros out there who has a similar board as the Z87X-UD3H to help me test if they encounter this? I am suspecting its the onboard power button.

 

[foo9883]

I'll say the SeaSonic PSU cause my SeaSonic also got a buzzing sound after shut down. I just switch off the main power then no more le.

 

[hwsinn]

I'll say the SeaSonic PSU cause my SeaSonic also got a buzzing sound after shut down. I just switch off the main power then no more le.

thanks for your input bro. I will definitely take your comment into consideration. But when i put my ear close to it, its more like its from my MB. Have to hear inputs from ppl with similar boards as so far from my steps of elimination, it doesnt point to the PSU (its 1 week+ old btw)

EDIT: the sound is more like high-pitched hissing or similar to gas/air leakage