Creating a representation of the base system architecture is one of the first and most critical steps for system development. Typically, the system architect would start by decomposing the existing or proposed system into smaller subsystems or modules. It is widely recognized that at the overall systems level a system can be viewed from different viewpoints. However, unlike often assumed, also when focusing on a single view, such as a systems view, the system decomposition can be done in many alternative ways thus resulting in a different base architecture every time. Depending on the system architect's perspective, representation of system can vary widely, having a profound impact on subsequent system architecture development. In this paper, quantitative analysis of system architecture representation, using a design structure matrix (DSM), and its effect on system modularity is presented. The analysis reveals that the results of the system analysis, namely modularity, are different for the same system, depending on the system architect's perspective. This work highlights the need for more structured approaches to system decomposition and system analysis based on that decomposition.