What Size Power Supply Needed

[paul]

The numbers 380 or 550 are virtually meaningless. What is important is
the quality, if the supply can actually do what it claims or not. If it
can, 380 is more than enough. If it cant, 550 may not be enough.

Antec is a high quality brand, and their 380 likely outperforms the
cheap 550s. Search Google for Antec TruePower review

This is absolutely true.
I just returned an Antec NEO 550 HE, as it was incapable of powering my
P5GD2 Premium MB.
The Asus tech suggested that the real concern was the rail current not the
"watts"

I then purchased an Antec NEO Power 480, because the rail currents (Amperes)
were considerably higher than those on the 550. My problem is now solved, as
the mobo needed more CURRENT not more "watts"