This presentation investigates the proximity to a low Signal-to-Noise Ratio (SNR) threshold that can still maintain a tolerable Bit Error Rate (BER) in 100G / 400G / 800G network links. Additionally, we account for factors such as temperature and cable length to predict the duration for which a reliable network connection can be sustained between transceivers. The analysis, based on data retrieved using a Flexbox, focuses on comparing the reliability of coherent (16QAM) and non-coherent (PAM4) transceivers, with a detailed discussion on the implications of these technologies on network performance.