With the end of Dennard scaling, three dimensional stacking has emerged as a promising integration technique to improve microprocessor performance. In this paper we present a 3D-SIC physical design methodology for a multi-core processor using commercial off-the-shelf tools. We explain the various flows involved and present the lessons learned during the design process. The logic dies were fabricated with GlobalFoundries 130 nm process and were stacked using the Ziptronix face-to-face (F2F) bonding technology. We also present a comparative analysis which highlights the benefits of 3D integration. Results indicate an order of magnitude decrease in wirelengths for critical inter-core components in the 3D implementation compared to 2D implementations.