Atomistic simulations are employed to probe the deformation behaviour of experimentally observed top-down and bottom-up face-centered cubic silver nanowires. Stable < 110 > oriented nanowires with s rhombic and truncated-rhombic cross section are considered, representative of top-down geometries as well as the multiply twinned pentagonal nanowire that is commonly fabricated in a bottom -up approach. The tensile deformation of a stable, experimentally observed structure is simulated to failure for each nanowire structure. A detailed mechanistic explanation of the initial defect nucleation is provided for each nanowire. The three geometries are shown to exhibit different levels of strength and deform by a range of mechanisms depending on the nanowire structure. In particular the deformation behaviour of top-down and bottom-up nanowires is shown to be fundamentally different. The yield strength of nanowires ranging from 1 to 25 nm in diameter is provided and reveals that in addition to cross-sectional diameter, the strength of the nanowires is strongly tied to the structure. This study demonstrates that nanowire structure and size may be tailored for specific mechanical requirements in nanometer-scale devices.