Currently, there is a challenge to improve properties of HPDC for increased strength and ductility. This can be achieved by consistent production of high-integrity HPDC castings. Process and alloy optimization can be done based on understanding the underlying fundamental processes. This article has also shown how solidifying material is transported through the partially-solidified gate during the intensification stage of HPDC. Based on this evidence, the feeding behavior in the conventional HPDC process and the high-integrity HPDC processes of squeeze casting and SSM is explained. It is likely that shear banding is a key feeding mechanism which can effectively reduce the porosity level in HPDC. This can be promoted by the combination of thick gates, high IP and small globular primary crystals. However, more research and development work is required to obtain an economic and robust HPDC process for high integrity castings, and optimizing the alloys for this purpose.