MARWAN speedtest

The test runs over HTTP/1.1 by default because it is the fastest of the three in a browser. It opens six separate TCP connections, and your computer's operating system handles them very efficiently, so it keeps up on links of several gigabits per second.

You can switch to HTTP/2 or HTTP/3 with the keys next to Start. HTTP/2 carries all six transfers over a single TCP connection. HTTP/3 runs over QUIC on UDP, the protocol most large websites now use; because the browser does much of QUIC's work itself, it usually tops out lower on very fast links. If your network blocks UDP, the browser falls back to HTTP/2 and the page tells you. Up to about 1 Gbps the three versions usually give similar results. The lights under the gauge show which version each request actually used, and your choice is remembered for next time.

Download and upload use six parallel requests for 10 seconds each. The first 1.5 seconds are left out so connection ramp-up doesn't pull the result down.

Ping is the median of 20 small requests on an idle connection. Jitter is the average change between consecutive pings.

Latency under load is the server's view of round-trip time while the download is running. A big jump over your idle ping points to oversized buffers along the path (bufferbloat).

Loss is measured by the server during the download: lost QUIC packets on HTTP/3, retransmitted TCP segments on HTTP/1.1 and HTTP/2. A web page can't send raw ping or UDP probes, so this is the closest reading of packet loss it can take. Pings that time out are listed next to it.