The aim of present work is to study the influence of microstructure and defects on the mechanical properties of a structural high pressure die cast (HPDC) component of a commercial Al-Si based foundry alloy, EN AC-44300. The alloy which contains mainly 12% Si and 0.7% Fe, is a successful application of a die-casting alloy for the automotive market. Tensile test specimens were extracted from both high pressure die cast components and from ones with comparable microstructures produced through gradient solidification technique, which offers specimens with low levels of defects. The microstructure and defects available in the component were well mapped via X-ray inspection system, optical and scanning electron microscopy. The results clearly confirmed the components' performance dependency to configuration of defects and Si morphology as well as revealed the potential of the alloy in terms of ultimate tensile strength and ductility.