>>>Thus, the question - would I be able to use whole 4G RAM with dual-core amd and
>>>kernel with SMP compiled for i686?
> 
> 
> Why would you use a dual core AMD in 32 bit mode?  Just build an x86_64
> kernel.
> 
> If you want to use 4GB in 32 bit mode, you *need* remapping (or you lose
> part of your memory).  Remapping means you have MORE than 4 GB of physical
> address, which means you need PAE to use it at all.

Because I find my distribution's 64-bit release reasonably unstable yet? :)

Or can I somehow build an x86_64 kernel and keep using 32-bit libc?