Bandwidth vs Latency
Bandwidth and latency are the two metrics ECE459 uses to define “fast”.
Why two metrics?
A program can improve on one without the other. Parallelization usually boosts bandwidth but leaves latency of any one request unchanged.
- Bandwidth: items per unit time, more is better, improved by parallelization
- Latency: time per item, less is better, matters most when users wait
High-bandwidth, high-latency
A truck of hard drives driven across a continent moves huge data per day (bandwidth) but any single byte takes hours to arrive (latency).
Nielsen’s rule: 100 ms is the ceiling for systems that claim to feel instantaneous. Google runs 8.8.8.8 partly because DNS latency compounds across every page load.