In this paper we evaluate parallel VHDL simulation based on conservative parallel discrete event simulation (conservative PDES) algorithms. We focus on a conservative simulation algorithm based on critical and external distances. This algorithm exploits the interconnection structure within the simulation model to increase parallelism. Further, a general method is introduced to automatically transform a VHDL model into a PDES model. Additionally, we suggest a method to further optimize parallel simulation performance. Finally, our first simulation results on a IBM parallel computer are presented. While these results are not sufficient for a general evaluation they show that a good speedup can be obtained.