Am 05.02.2011 16:45, schrieb Paul Stear:
> Sorry original sent to the wrong list.
> 
> Hi,
> I am currently using amd64 2 core processor but now have the chance to use 
> an intel quad 64 processor.
> This might be a silly question but is it best to do a compltly new install?
> If so which stage do I download from the following list:-
>  
>  alpha: iso stages 
>  amd64: iso stages 
>  arm: stages 
>  hppa: stages 
>  ia64: iso stages 
>  ppc/ppc64: iso stages 
>  s390/s390x: stages 
>  sh: stages 
>  sparc: iso stages 
>  x86: iso stages
> 
> Which chost and cflags should I use?
> 
> Thanks for any help
> paul

It's amd64, as well. Unfortunately, depending on your CFLAGS you might
still have incompatible code on your current system. You can still try
it but you will likely encounter random process crashes because of
invalid opcodes.

You can avoid a complete reinstall by changing your CFLAGS to something
generic like '-march=i686' and remove anything else not supported by
both processor families.
Then make a `emerge --emptytree world` to recompile all packages.

Don't forget to adjust your kernel as well.

For your specific CFLAGS, look here:
http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel

Hope this helps,
Florian Philipp