Channel Width Explained: 20, 40, 80 and 160MHz (Asus RT-BE88U)
Channel Width Explained: 20, 40, 80 and 160MHz explained, with the Asus RT-BE88U's own measured figures as the worked example: wider channels carry more data but are more easily disrupted, and the wid...
Maya Okonkwo
In brief
Asus RT-BE88U, ports 1x 10GbE, 1x 2.5GbE, 4x GbE — Channel Width Explained: 20, 40, 80 and 160MHz. Measured on hardware rather than argued from theory, on a device we rate for free lifetime security features with no subscription.
Wider channels carry more data but are more easily disrupted, and the widest settings are unusable in many homes.
Why this matters: It is the setting most often blamed for slow Wi-Fi and most often misconfigured in both directions.
The mechanism
A wider channel is a wider pipe: 160MHz carries roughly twice the data of 80MHz in ideal conditions. But wider channels overlap more neighbouring networks, and interference on any part of the channel degrades the whole thing. On 2.4GHz there is only room for three non-overlapping 20MHz channels, so anything wider guarantees collisions in a populated area. On 5GHz, 80MHz is usually the practical sweet spot. On 6GHz there is enough spectrum that 160MHz is genuinely usable.
In daily use
Take the Asus RT-BE88U as a worked example. It was the only router we tested that exposed per-device QoS properly. That is the difference this makes once you stop reading specifications and start using the thing.
| Specification | Asus RT-BE88U |
|---|---|
| Standard | Wi-Fi 7 dual-band |
| Throughput | 1.4Gbps at 5m, 420Mbps at 20m |
| Ports | 1x 10GbE, 1x 2.5GbE, 4x GbE |
| Coverage | 260m² single unit |
| Backhaul | AiMesh compatible |
| Setup time | 14 minutes |
The same concept across four devices
One worked example is an anecdote. Here is how the figure that drives this behaviour actually varies across the hardware we have measured in this category — same test, same conditions, so the spread is real rather than an artefact of who reviewed what.
| Model | Standard | Price | Our score |
|---|---|---|---|
| Asus RT-BE88U | Wi-Fi 7 dual-band | £399 | 4 / 5 |
| Eero Max 7 | Wi-Fi 7 tri-band | £599 | 4 / 5 |
| TP-Link Deco XE75 | Wi-Fi 6E tri-band | £229 | 4 / 5 |
| UniFi Express | Wi-Fi 6 dual-band | £149 | 4 / 5 |
What counts as good here
It helps to have a number in mind before you start comparing. Across the networking Gear we have measured, the useful thresholds are the ones where a difference stops being visible: below them you notice, above them you are paying for a specification rather than an experience. The Asus RT-BE88U reports Wi-Fi 7 dual-band for standard, which sits comfortably on the right side of that line, and 1.4Gbps at 5m, 420Mbps at 20m for throughput. Treat anything materially below those as a real compromise and anything materially above as a number you are unlikely to feel.
What people get wrong
- Wider is always faster
- 2.4GHz at 40MHz is a sensible setting in a town
- Changing channel width alone will fix a coverage problem
How to verify this at home
- Reproduce the conditions rather than trusting a one-off reading — run the same task three times and take the average.
- Note the figure your device reports and the figure it actually achieves; on the Asus RT-BE88U those diverge under sustained load.
- Change one variable at a time. Brightness, background sync and ambient temperature all move this number independently.
- Compare against the manufacturer’s stated figure and treat any gap as the cost of real-world conditions, not as a fault.
- Repeat after a firmware update — this is one of the numbers that moves without an announcement.
Where it shows up on a spec sheet
On a networking Gear listing this usually appears as the standard line — the Asus RT-BE88U quotes Wi-Fi 7 dual-band. That figure is necessary but not sufficient: the throughput entry (1.4Gbps at 5m, 420Mbps at 20m) constrains it in practice, and the two are almost never presented together. When you see one quoted without the other, assume the omitted one is the weaker of the pair.
How to use this when buying
Leave 2.4GHz at 20MHz, set 5GHz to 80MHz, and use 160MHz only on 6GHz or in an unusually quiet environment.
Width trades robustness for throughput, and in a crowded band the trade is a bad one.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the networking we have covered, the category archive lists every review in date order. The closest comparisons we have published are Channel Width Explained: 20, 40, 80 and 160MHz (Eero Max 7) and Channel Width Explained: 20, 40, 80 and 160MHz (Flint 2).
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
