Commercial application of Optical Packet Switching to backbone WDM networks is still far from reality due to hardware costs. The two envisaged alternatives for network control and operation of this type of networks are Scattered Wavelength Path (SCWP) and Shared Wavelength Path (SHWP). The advantages and drawbacks of both approaches involve many different issues. In this paper, the impact of SCWP and SHWP switching modes on performance and hardware costs is discussed and evaluated for three different prominent OPS switch fabric designs: KEOPS switch, space switch, and output-buffered wavelength-routed switch. To achieve it, we conduct a necessary set of modifications for these architectures, which were not originally conceived for SCWP/SHWP. This normalization process is unavoidable to provide a true comparison among the switch fabric designs, and to advance to a global comparison between SCWP and SHWP operation modes, that under knowledge of the authors do not exist yet.