Just curious. PC powers up, then down, then up again- why?

[Nocky24]

My ocz psu in my q9550 build does this on cold boot everytime and i'm just curious as to why? The pc and overclock is perfectly stable and has primed for many hours so i can rule that out. Is it a safety feature or something to do with it being a switched-mode power supply? I've seen other people with ocz psus do this on them at startup so i'd just like to know why

 

[Nocky24]

Any ideas? :/

 

[VTR]

System in sig does the same, it's normal, not sure why it does it but it's nothing to worry about.

 

[Temi_D]

Mine does the same too, its normal apparently