dfi lanparty - anyone else having problems w/ this MB?

I purchased 2 dfi lanparty UT nF4 SLI-D MB's some time ago.
I have ALWAYS had the identical problem with BOTH MB's.
when I want to power them on - they will only power on if they feel
like it. I have to power off the PSU (or unplug it), and power it back
on, and hit the power switch & pray the dam thing powers up.

I repeat this process until the thing finally does power on. I rarely
power off these pc's, so this has been an irritation that i've
overlooked... but I'm really getting frustrated with the problem.

Both PC's have a 500W PSU - and not cheapo's (dual rails; plenty of
A's). I wasn't sure if the problem was with the PSU, so I replaced one
with a different brand. Both still have the same problem.

furthermore - I'm using striped raid on both MB's, and BOTH have had
(as best as I can describe) periods of really glitchy wierd HD issues.

both MB's have the latest bios update (406)

am curious if anyone else has had similiar issues, and what, if any,
they found for a resolution...???

TIA - Bob