As the industry moves from single- to multicore processors, the challenges of how to reliably design and analyze power delivery for such systems arise. We study various workload assignments to cores and their effect on the global power supply noise and ground bounce. We provide a detailed analysis of single and multiple cores and develop analytical formulas to capture the power supply noise and ground bounce of the system. We introduce metrics to estimate the amount of noise propagated from core to core and propose a supply noise aware workload assignment method. In our experiments, we show that timing constraints can be significantly affected if workload assignments are not properly made.