I just set up a new OpenBSD box on a C2D / DG965RY motherboard and everything works great. In the recent 4.0 changes it looked like everything was now supported, however that turned out not to be the case. Whenever I try to boot bsd.mp it gives "kernel protection fault," "pci_intr_map: no mp mapping," and "isa_intr_establish" errors.
I found some pretty old stuff in the archives talking about a bios issue that someone had been working on intermittently, but nothing that relates very closely. I ran into a bit of trouble trying to obtain a dump when I realized that the board doesn't have a serial port - so sorry for not including it. I suspect because this is such new hardware the developers just haven't had the opportunity to add the correct drivers to the 4.0 release and it is in current or will be in 4.1. Does anyone know if this is just an issue that people are working on or a bug I have stumbled upon? I will try to include a dump in a later post if it will be of use to someone. William