Can you make some CPU specific binaries for linux?

compilation options for gcc:
-mtune=generic (you probably are using this for your linux version)
-march=core2 (for us Core2/i7 positive ppls )
and maybe something for AMD ppls too ;-)
-march=k8-sse3 (dunno if non sse4 is supported ehm)
-march=amdfam10

I am just curious about generic vs CPU specific binary speedup. (I saw somewhere, that AMD CPU's are really much better with optimizated binaries...)