em64t vs amd64?

[Petr Stehlik]

Rano,

mam dobrou zkusenost s amd64 na serveru, a ted jsem dostal nabidku na
IBM x226 s Xeonem s em64t. em64t ma byt kopie amd64, ale nevim, jak
dobre to "obšlehli". Chci na tom valit 64bit debian sarge. Ma nekdo
nejakou zkusenost? Google nasel vety typu "xeon slows down a little in
general when you enable 64bit mode. AMDs speed up. Given the AMD is
usually faster at mosts tasks already in 32 bit mode, the situation is
not improved 
(for intel) in 64bit mode.", coz me zrovna nenadchlo.

Petr