In article news:<ejih0n$5fa$1@nemesis.news.tpi.pl>, Pawel Kraszewski wrote:
> AMD64 are amd64/Opteron and - surprise, surprise - all chips from EM64T
> family, including new P4 and new Core/Core2 chips.

I believe that's nearly right: Core Solo/Duo chips are 32-bit only (no
EMT64 instructions), but Core 2 Duo/Quadro chips do have EMT64.

The OP's E6300 is a Core 2 Duo (Allendale) chip, so does have EMT64, and
should use AMD64 Gentoo binaries.

Cheers,
Daniel.