Power down sound but not powering down?

[orangeman2003]

Basicly changed my motherboard in the last few weeks and only just noticed this new sound every now and then but im not sure if it is related to the motherboard or not.

Asus P5P41C
Thermaltake ultra 120 extreme + 120mm yates
C2D E6600
4GB Corsair DHX
ATI 4890
520w corsair PSU
2 120mm case fans

Basicly everyone knows the sounds a pc makes when its just switched off and everything looses power and winds down well every now and then the pc will make this noice but nothing happens to the pc, it will stay on no BSOD or freeze or anything. Ive had this happen when just surfing the web but not sure if its happened when gaming as i have headphones on but i get no issues when playing games either, been playing Mafia 2 and other latest titles with no issues.

When this has happened and ive heard it ive gone straight to the pc inside to check all fans are spinning as normal aswell as checking all temps on the pc and everything is the same as norrmal. Ive checked all fans inc psu fan and all are still spinning.

Does anyone know what i should do from here???? As this noise cannot be normal right? PSU is a few yrs old but cannot say its that as i have no proof, GFX card just over 1 yr old with warranty still but cannot 100% its that either. I see no signs when looking in the pc as to what it could be

Any help would be great

Thanks

 

[cmndr_andi]

When you say "the sounds a pc makes when its just switched off and everything looses power and winds down", do you mean a you hear a beep or is it that you are hearing all the fans turn off while your PC is still running?

 

[orangeman2003]

no beeps or anything, its as if the pc is making the same noice that the pc should make when powering down i cannot really think how else to describe it.

But as ive said above no fans stop spinning or anything.. im kinda stumped as to what part is causing this.

 

[Tealc]

Is this a hard drive spinning down into sleep mode perhaps? If you've got a drive that sends vibrations through the case then when it powers down you'll hear the difference.

I remember being quite surprised at the difference when my hard drive was mounted in a cage and I spun it down using a WD Gard drive diagnosic app. After this experience I isolated them with elastic.

 

[orangeman2003]

wow 100% thats what it is, i changed the setting from 20 mins to 2 and it made the same noise after 2 mins.

I never heard it before i think this might be because i swapped to a different drive as main and an old one as a drive for storage which doesn't get accessed much if at all. So seems my WD drive is louder than my seagates lol, kinda makes me wanna swap them back around lol

Thanks for your help i thought it was a PSU or GFX card issue