The paper highlights how the latest ONT test modules (N-PORT, 800G) can test latency up to sub-nanosecond resolution. With stressed latency testing users can get a unique picture of how latency in ICs, optical modules, and network elements really varies under true operating conditions and can quickly identify weak links and anomalies. This document explains the need and applications of high-resolution stressed latency and shows how to get the best results using the VIAVI ONT family.