> In my case the motherboard when plugged in by itself with no other
> cards or peripherals refuses to power up.  This is when hooked to
> a Seasonic S12-430 (ATX 2.x) 400watt power supply*.

I wrote to Tyan and Seasonic support asking about this, as I was
interested in the same combination, and the S12-430 looks very similar
to the Seasonic SS-401HT which Tyan recommends, but appariently isn't
sold here.

Tyan says that the SS-401HT meets the EPS12V spec, and hinted that
these specs have differences in signaling.  I suspect the timing of
the power_okay line is critical.  (If anyone is actually interested
in this issue, email me off list and I'll send you some URLs.)

Some pros of the Tyan K8E:

	more I/O than other boards

	Can support 4 GB of RAM.

	The firmware has an option for ECC scrubbing.  Word is that some
	mainboards don't even bother running the traces from the AMD64 to
	the RAM.  What tiny fraction of a penny does that save?

	You can use a rs232 console if you want.  Appariently some
	pee-cee-ish boards require a video console.

	No fan on the nforce4 chip.  (Which is likely to be an oddball size
	and hard to find a replacement for when it dies.)

	Tyan's website has some useful info.  The manual is online.  A decent
	resolution photo of the board is online.  Recommended P/S, memory, etc.

And some cons:

	It took Tyan a month (exactly) to reply to a question.
	and they didn't answer all my questions.  On the other hand,
	I still haven't received a reply from Seasonic.

	If you want to use a video console (as opposed to rs232)
	you need a prehistoric low end monitor that can do 640x480.
	640x480 was low end 20 years ago.  A CRT can't do 640x480 *and*
	do high resolution *and* do them well.  (typical quality vs
	flexibility tradeoff)  Or you can look into scan converters.  Or
	you can look into LCDs, which presumably include an internal scan
	converter, and which have their own tradeoffs (dead pixels, ...).

	P/S needs to meet EPS12V spec.