To ensure backward compatibility the new AM2+ and AM3 (H2 2008)
performance motherboards will use 125w 95A Dual-Plane VRMs. This could
make future motherboards more expensive although it makes them universal
with AM2 processors - not sure if in the case of AM3 though.
In the mainstream and value parts, motherboards will use single-plane 89w
80A VRM, and this may tell us that they won´t be backwards compatible.
I did not post presentations or original diagrams this time, because they
are watermarked, but I made a diagram according to the info you can check