Just be careful which 64-bit version you grab.  Some distros (like 
Debian) only have official support for the IA64 architecture (Intel 
Itanium), and the x86_64 architecture (AMD Athlon 64 and Opteron) is a 
separate, incompatible, architecture.  There have been a couple of 
distributions based off of other projects that failed to understand 
this, and are distributing an IA64 build as an x86_64 build, and it 
crashes, badly, when you try to run it on AMD hardware.
There are a few distros that support both IA64 and x86_64, in that case, 
just make sure you grab the right one, since both are labeled as 64-bit 
builds.

George Joseph Thekkekara wrote:

>All popular flavors like Fedora, Gentoo, Mandrake, RedHat, SuSE all
>have precompiled version of their OS for AMD64. Try one of them.
>
>Regards
>
>George Joseph
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