Why Is My Wi-Fi Slow After the NBN Upgrade?

Why is my Wi-Fi slow after the NBN speed upgrade?

By Pasan, founder and lead technician at Sysworth IT · Updated 2 November 2026

Quick answer

The most common reason is the router: after the NBN speed upgrades, many older routers cap a home at around 100 Mbps. Thick walls, a modem in the wrong spot and too many devices create dead spots. Test speed at the modem, then in each room; if it is fast at the modem but slow elsewhere, it is a Wi-Fi problem, usually fixed by moving the modem or adding mesh.

Step 1: find out where the slowdown is

Run a speed test on a laptop plugged into the modem with a cable, or standing right next to it. Then test in the rooms where it's slow.

Slow at the modem too: it's the plan, the NBN connection or the router itself. Check your plan speed and router model.
Fast at the modem, slow elsewhere: it's Wi-Fi coverage. Read on.

Step 2: quick fixes worth trying

Move the modem out of cupboards and away from the floor, TVs and fish tanks.
Restart the modem and update its firmware.
Use the 5 GHz network for devices near the modem.
Unplug old extenders that create a second, slower network.

Step 3: when you need new equipment

If your router is more than five years old or the house is long or double-brick, a Wi-Fi 6 mesh system usually solves it. Buy only after testing: many Adelaide homes are fixed with settings and placement alone.

Our Wi-Fi Fix & Boost ($159) tests every room, checks you're getting the speed you pay for, fixes settings and sets up mesh only if needed, at a written price.

Do I need a new router for faster NBN?

Often, yes. Many older routers cannot pass on speeds above about 100 Mbps, so homes on faster plans see no improvement. A Wi-Fi 6 router or mesh system usually fixes it.

Is mesh Wi-Fi better than an extender?

Usually. Mesh units work as one network and hand your device between them smoothly, while cheap extenders often halve the speed and create a second network name.