Mobile Web browsing advancements have largely been driven by the single-minded pursuit of performance. In this paper, we take a different stance and examine the energy efficiency of mobile Web browsing. Focusing on both the network and CPU, we find that generational advancements in network technology have reached a point where the mobile CPU is starting to have noticeable impact on Web browsing performance and energy consumption. Achieving energy-efficient mobile Web browsing requires considering both CPU and network capabilities (i.e., latency). We show that under different network latency conditions, achieving energy-efficient mobile Web browsing mandates different CPU performance capabilities. It is important to understand and leverage such interactions between the network and CPU in order to deliver high mobile Web performance while maintaining a low energy footprint, which current OS DVFS governors fail to achieve. Our findings suggest that designing future high-performance and energy-efficient mobile Web clients implies looking beyond individual components and taking a full system perspective.