Power Supply Issue? Dual Xeons

[DataSurfer]

I just built a dual Xeon system and am a lot having trouble with it. The system will boot if I leave it off for a few hours. If I reboot, or shutdown and turn on, the LEDs come on, the fans kick on, SMC heartbeat comes on, but the board does not come to life or POST. (Sometimes the power light on the mobo comes on, sometimes it doesn't)

The PSU seems logical, but I don't know; I have some questions:

I have a RAIDMAX 850watt power supply with the 24 pin connector, 1 EPS (8 pin) and 1 4+4 connector. Both the 8pin and the 4+4 are labeled as "CPU" power. Is 850W enough? Too much? Should all 40 pins be connected to the motherboard? Anything else worth trying?

 

[king smp]

I would definitely try a different PSU
Check out JohnnyGuru for advice and recommendations
http://www.jonnyguru.com/index.php
basically stick with Antec,Corsair,Seasonic,XFX and other major names
I have heard recently for cheap PSUs that the RocketFish 80+are alright
and also heard that Xigmatek is decent
but going with a JohnnyGuru recommended PSU is a good idea