Does More Bandwidth Really Not Matter (Much)?
This paper challenges the conventional wisdom that bandwidth is negligible and latency dominates web performance, systematically investigating the actual impact of mobile network bandwidth and latency on modern complex web pages. Method: We propose a novel metric—Critical Path of Improvement (CPI)—to quantify websites’ sensitivity distributions to bandwidth versus latency. Leveraging real-world network measurements across four operators and 57 cities, we construct an empirically grounded CPI model and perform critical-path decomposition and correlation analysis. Contribution/Results: Our findings reveal that 18% of websites are predominantly bandwidth-limited, while over half exhibit significant bandwidth sensitivity. The study uncovers the underappreciated role of bandwidth in mobile web performance and delivers a practical, deployable framework for diagnosing bandwidth sensitivity—providing empirical guidance for developers optimizing resource loading strategies and operators designing differentiated QoS policies.