Fast internet can still feel slow

Four different things

• Bandwidth is how much data the connection can carry at once, measured in megabits per second. It is what internet plans advertise.
• Latency is the delay for data to travel there and back, measured in milliseconds. High latency makes conversations awkward, with people talking over each other.
• Jitter is how much that delay varies. Calls need a steady rhythm; uneven delay makes voices choppy.
• Packet loss is data that never arrives. Even a little causes frozen video and words dropping out.

Why speed tests can mislead

A speed test mostly measures bandwidth, often to a nearby server, at one moment. Video calls and phone calls need low, steady delay and almost no loss, all the time.

Common causes

• Upload speed is too low. Many plans have fast downloads but slow uploads, and your video goes up.
• Someone is using all the bandwidth, such as a large backup or file upload during the workday.
• Wi-Fi problems: weak signal or interference adds delay and loss before traffic even leaves the building.
• No priority for calls on the network.

What helps

Check upload as well as download speed, schedule big transfers out of hours, use a cable for desk computers where possible, and set the network to put calls first.