Speed test
Pulls real files off this server and times them.
Measured
Passive estimate vs measured
The passive estimate is snapshotted when the test starts, before the test's own traffic can teach it anything.
Detail
| no run yet |
Incompressible files only — a CDN gzips text, and the reader would count bytes that never crossed the wire. Measures the path to the nearest edge, not your line. Uploads are posted to a static path and refused; only the ones whose body finished are counted, and a host that refuses part way through yields no figure rather than a wrong one.
The duration is a ceiling, not a length: each direction stops as soon as the last second only repeats what the run has already said, which on a quick link is a second or two rather than ten. What that cannot get around is arithmetic — a second of a 2.5 Gbps link is 300 MB, so measuring one honestly costs that. The cap is the ceiling on what the whole test may spend; when it bites before a full window has formed, the figures are marked as a floor on the link rather than a measure of it.