Updated: 2026-05-08 · By Cabling For U · 8 min read

Why your 1 Gbps fibre plan is delivering 50 Mbps — and what to fix in 2026

You signed up for 1,000 Mbps fibre. Your speed test says 50. Your Zoom calls drop. Your kids complain. Here’s exactly why — and the four fixes ranked by cost, in order of biggest payback.

How fibre actually reaches your laptop

When Chorus or 2degrees turns on your fibre plan, here’s the chain:

1. Fibre comes into the house at the ONT (the white box on the wall, often in the garage or laundry).
2. An Ethernet cable runs from the ONT to your modem/router. Almost always Cat5e or Cat6.
3. The modem broadcasts WiFi. Or sends data via Ethernet to other rooms.
4. Your laptop / phone / TV receives. Usually via WiFi, sometimes via wall socket.

Each link in that chain has its own speed limit. The 1 Gbps you’re paying for is the speed of step 1 — fibre into the house. Steps 2, 3 and 4 each cap what you actually receive.

The four real bottlenecks (ranked by how often they cause the problem)

1. ISP router WiFi (causes ~70 % of slow-speed complaints)

The router your ISP gives you (a Vodafone Ultra Hub, Spark Smart Modem, 2degrees Smart Modem, etc.) is designed to be cheap, not strong. Its WiFi covers one floor of an average NZ home, struggles through internal walls, and tops out at around 100–300 Mbps even at close range — not 1,000.

Your fibre plan can deliver 1 Gbps. Your ISP’s router can’t broadcast 1 Gbps over WiFi. That’s the gap.

Symptom: Speed test on phone in same room as router = ~300 Mbps. Speed test in master bedroom = ~50 Mbps. Speed test plugged in via Ethernet = full 1 Gbps.

Fix: 2–4 ceiling-mounted access points (Ubiquiti UniFi, Aruba, TP-Link Omada) with Cat6 cable backhaul to each one. About $1,200–1,800 fitted for a 3-4 bedroom home. Solves the problem in one day.

2. Old Cat5 or Cat5e cabling between rooms (causes ~15 %)

If your home was built before 2010, the data cabling in the walls is likely Cat5e — rated for 1 Gbps but only at short distances and only if perfectly terminated. Cat5 (no “e”) caps at 100 Mbps regardless of your fibre plan.

Symptom: Even plugged in via Ethernet, you only get 100 Mbps in the bedroom or office.

Fix: Re-cable with Cat6 or Cat6A. About $480–1,200 fitted for a typical home. Future-proofs you for 10 Gbps fibre when it arrives.

3. Old Ethernet cable to the modem (causes ~10 %)

The cable from the ONT to your modem might be Cat5e from 2014. Replace it with a 1-metre Cat6 cable from any electronics store (~$15). 30-second fix.

Symptom: Speed plugged in via Ethernet to the modem doesn’t exceed 300–500 Mbps.

4. Your laptop / device (causes ~5 %)

An older laptop with WiFi 4 or WiFi 5 can’t actually receive 1 Gbps over WiFi. WiFi 6 (802.11ax) hardware is required.

Test: Plug a recent laptop into the modem via Ethernet cable. If it gets 900+ Mbps wired but only 200 over WiFi, the device is the limit.

Quick diagnostic — do this before booking anyone

1. Plug a laptop into your modem via Ethernet. Run fast.com.
2. If you get 900+ Mbps wired: your fibre is fine. The problem is WiFi or in-wall cabling. Skip to fix #1.
3. If you get 300–700 Mbps wired: the cable from ONT to modem is old. Skip to fix #3.
4. If you get under 300 Mbps wired: ring your ISP. Likely a fibre fault or wrong plan.

What does it cost to fix, ranked by payback

The Auckland-specific bit

Auckland homes built before 2010 almost universally have Cat5e in-wall cabling at best. Hobsonville Point and other newer developments tend to have Cat6 pre-wired. If you’re renovating or moving into an older home, this is the moment to upgrade — opening up the walls for any reason makes the cabling job 30–50 % cheaper than retro-fitting later.

If you want a free 30-minute survey of your home, including a WiFi heat-map, we walk through the property and show you exactly which fix would solve YOUR problem — not the generic answer.

Common questions