Relative metal softnesses

I’ve been experimenting with knots and wire, in copper that I was
told was “dead soft”, but then it occured to me that "dead soft"
copper was probably very (?) different than “dead soft” sterling,
fine silver or gold (but based on the amount of copper that I’ve
kinked up so far, I’m not getting anywhere near gold! 8) So, my
question is: how much difference is there in the softnesses of the
various “dead soft” wires?