In this paper, various models of carbon nanotube (CNT) and NiSi nanowire are established and used to analyze their performance as future on-chip interconnections. These theoretical studies and simulation results lead to important new findings: NiSi nanowire has superior properties in terms of effective current density and propagation speed compared to Cu and CNT. These properties make NiSi nanowire the most promising candidate for future on-chip interconnections. Bundle CNT also shows promise for long interconnect applications