Programs memory usage in AMD64

[Francisco Reyes]

Before I got an AMD64 motherboard for a client I asked about memory usage. 
I was told that it was higher than i386.. perhaps twice as high.

I am finding it's considerably higher. For example

sshd takes under 3MB in i386. It takes close to 30MB in AMD64!

csh takes 2MB in i386 and almost 6MB in AMD64. Not as bad as sshd, but 
still almost 3 times. :-(

Why is it that programs take so much more memory in AMD64?