Strange PC noise

[StonedOwl]

Hello guys,

So recently i bought a new PC, build it myself:
i7 8700
gigabyte gtx 1070 g1
msi z370 krait gaming
G.SKILL 16GB Trident Z DDR4 3200MHz
evga g2 750w
segate barracuda 2tb
samsung 960 evo 500gb
cryorig h7
corsair carbide spec 02

And everything is working fine, but i keep getting random noise from my PC, best i can describe it is its the same type of noise i hear when i power on my pc or when i wake it from sleep, so its a short "wroom" sound followed by sound of some fan starting and speeding up and then at the end few crackling motherboard sounds. And this happens randomly in gaming, watching youtube, even when its idle.

I have been monitoring my temps and everything is normal, also i have been trying to find out what is the source of the noise but couldnt pin point it, but i have ruled out my GPU fans since i saw that they are not spinning once the random noise occurs, also i have tried putting my PSU on ECO mode but that didnt give any results, so it keeps occurring with my PSU fan spinning and when its in ECO mode.

At first i used supplied case fans, but later i changed them with 3 thermaltake ones, but noise happened with both fan setups.

So I really dont know, that leaves me with CPU cooler fan but i can hear that when it speeds up when i render videos and its not same type of fan noise that happens.

In general it doesnt bother me that much, but would appreciate if anyone here has any idea to what could it be, since it may be something dangerous.

 

[geofelt]

If your motherboard has a speaker, you might be hearing some of that on startup.
Initially, the motherboard may run the cpu fan full out until it knows that the temperature is ok.

Since you can reproduce the sounds, take a rolled up paper tube and use it as a stethoscope to try to pinpoint the offending part.
You may need to remove the case covers to do this.