My friend smashed his mobo

[theisrafil]

Ok long story short:
He bought a 600w psu but the fans werent spinning, so he plugged a 4 pin cable to the 3 pin PWR_Fan socket. Then a smoke came from that socket as he says. I know he did a dumb thing. Psu is a 600w cooler master and the mobo is gigabyte ep45t ud3r. Please tell me what is the possible damage here? (apart from mobo) Cpu is xeon x5460

 

[Darthutos]

It shouldn't be a problem with 4 pin to 3 pin as long as you got the direction of the key right. I think he might have pushed the 4 pin in the wrong direction and causing polarity trouble.

Since there was smoke coming out it's safe to say his motherboard is not to be trusted anymore and considered broken.