Upgrading hardware from P3 to AMD 64

[RW]

I'm thinking about upgrading my hardware from an Intel P3 to an AMD 64, and 
replacing the graphics card, without buying a new hard disk. Has anyone done 
this kind of thing successfully? 

I've recompiled kernel+world for 686 and I've done a portupgrade -fR on cvsup 
and portupgrade.

Typical motherboards now have a couple of sata connections in addition to the 
normal ide connections. Can I expect my current ide drives to still be ad0 
and ad1?