ATX secondary power

Hey guys, I am helping a person I know with his server. Someone else just built this server for him, but didn't do a very good job. My question is this, I notice this mobo has a secondary atx power plug and the psu has the secondary atx power plug. Is there any reason to not plug in the secondary atx power?? Is there any benefit?? The Mobo manual says YOU MUST PLUG IT IN, but this server has run for several days without it plugged in. Thanks

I wouldn't take a chance. As far as I know, ATX Mobo's were meant to have 2 power plugs. I read what the second did, but I can't recall the exact importance.

Plug that puppy in!!!!!