The anisotropy of the threshold energy for atom displacement,Ed, in Au and Ag at 473 K has been determined. Whereas in Ag, minima ofEdare found close to the ⟨100⟩, ⟨110⟩ and ⟨210⟩ directions (Ed= 13–18eV), atom displacement in Au requires least energy near ⟨100⟩ (15–19eV). So far Au is the only f.c.c. metal exhibiting a distinctly lowerEdin the ⟨100⟩ than in the ⟨110⟩ direction. This is discussed in terms of the atomic processes controlling the propagation of replacement collision sequences.