The 401 might just not support the Engineering Samples, the Retail Versions hopefully will work with any P5W bios, or atleast I hope that's what happens. Don't wanna buy a 805 to install, then switch the bios :/
I'm sure a lot of people are hoping that the 0401 bios will support retail conroes. It probably will, otherwise Asus is going to have a lot of pissed off customers, me included.
The P5W DH I received from eWIZ came with BIOS version 0502 installed. It seems some vendors are shipping this board with a BIOS that will support Conroe right out of the box, while some others are not. It's the luck of the draw at this point.