Update on Seasonic problems
Tong Family Blog: DFI LanParty nF4 Ultra D problems. An update on my DFI LanParty problems. I got an Enermax 600W power supply and these boot problems disappeared. Now it appears that there is a fix for the Seasonic power supplies and their 5VSB issues, so you have to contact Seasonic to get a new power supply.
Even the fancy new S12-600 had it and you have to make sure you have Revision A3 so you can boot off of DFI LanParty.
I'll have to see about whether that applies to my older Seasonic SuperTornedo 400