Hi,
 
I'm right now installing a P5K-E WIFI-AP and a ZM600-HP PSU.
The PSU has a 20+4 pin which I connect (both sections) to the 24-pin ATXPWR of the board.
I'm not sure about wether or not to plug a 4-pin cable on the 8-pin ATX12V connector.
Tried to turn it on without it and the fans run for one-sec the shut off.
It seems to me from the manuals that I shouldn't plug two 4-pin's to fill it.
 
Should I plug one 4-pin cable to the 8-pin ATX12V ?  
 
Thanks!

The 4/8pin is required for modern cpus. Yep, plug the 4-pin in the 8-pin connector by the cpu.
 

 
See the black cap on the other 4-pin? Leave it there. Plug your cable in the other open side. Make sure the latch is on the same side & the prongs match.

Thanks!
Now I see why I as afraid of that, my mobo didn't come with the cap! And so far I haven't seen any picture of it with the cap.
 
Thanks again!

it only fits in one way