As network applications become increasingly sophisticated and Internet traffic is getting heavier, future network processors must continue processing computation-intensive network applications at line rates. Most programmable network processors on the market today, such as the Intel IXP2800, target relatively low performance (from 100 Mbps to 10 Gbps). However, low cost edge routers will find it hard to cope with the forthcoming sophistication of network applications to be processed at those speeds. Hence, new architectures should be designed for the programmable network processors of the future. The goal of this paper is to evaluate the applicability and efficiency of Simultaneous MultiThreaded (SMT) as the base architecture of a network processor. Indeed, the SMT model inherently allows the multiple parallel threads which must be dealt with in network processor applications. In this paper, we investigate the architectural implications of network applications on the SMT architecture. We demonstrate that, when executed as independent threads, applications chosen from different network layers show an improved Instructions Per Cycle (IPC) and cache behavior when compared with the situation where the program executed comes from a single network application. Finally, a new architectural solution to cope with packet dependency is proposed and evaluated.