The continuous quest for energy-efficient computing has led towards the adoption of fine-grained controls in processor sub-systems, of which power delivery network is the most prominent one. Recent industry trends reflect a shift towards on-chip, integrated voltage regulator (IVRs) to that effect. We undertake a thorough and quantitative evaluation of different power delivery networks for modern microprocessors. In contrast to the current trend, we conclude that IVR schemes perform worse compared to the conventional off-chip voltage regulator scheme. Further, we present studies on diverse workloads and Thermal Design Points (TDPs) to highlight the importance of workload-specific power delivery scheme. To the best of our knowledge, this is the first comprehensive study across processors' TDPs and workloads.