To meet the challenges associated with transistor scaling and short channel devices, the structure of MOS devices has undergone an incredible evolution. From Bulk devices, technology has shifted through Silicon-On-Insulator (SOI) devices, reaching now FinFET transistors, the next steps in the evolutionary path are represented by Gate-All-Around (GAA) and Molecular Transistors. Using analytical compact models for standard (BULK, SOI, FinFET) and emerging devices (GAA, Molecular FET (MOLFET)), it is possible to predict the system level performance of future NANO electronic circuits. In this work, we show how circuit's performance can be predicted and analyzed at system level using our tool, TAMTAMS Web. Starting from Bulk transistors down to a nanometer scale Molecular FET, TAMTAMS Web incorporates models to analyze device quantities (Drive current, Subthresold current…) up to system level. We have developed a compact model of Virtex 4 FPGA CLB block that is used as benchmark. The work here presented not only highlights the potentialities of TAMTAMS, but it also provides useful hints on the evolution of transistor based technology.