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Dual-band vs Tri-band 101: The Best Clues

For years, I’d received a lot of questions regarding Dual-band vs Tri-band in Wi-Fi routers. Folks were super undecided between broadcasters like the Netgear RAX200 vs RAX120 or the Asus GT-AX11000 vs RT-AX89X.

Then 2021 came along, and now there is also a new tri-band option: The Wi-Fi 6E standard. Things start to get even more confusing.

So, I’ll explain here the differences between Tri-band and Dual-band and how they affect standalone broadcasters.

But if you’re in a hurry, here’s the gist: It doesn’t hurt to go with a tri-band router, and in some cases, you can even say you need one. But most of the time, investing in an additional band is unlikely money well-spent.

OK, let’s start with dual-band.

Dong’s note: I first published this post on October 28, 2019, and last updated it on September 17, 2021, to include additional relevant and up-to-date information.

Dual-band vs Tri-band Wi-Fi: Netgear RAX200 vs RAX120 Wi Fi Routers
Dual-band vs Tri-band Wi-Fi: You can hardly tell the dual-band Netgear RAX120 (top) and the tri-band Netgear RAX200 apart, appearance-wise, and, for the most part, also in Wi-Fi performance.

Dual-band Wi-Fi: It’s all about compatibility

Dual-band goes back to the 802.11n Wi-Fi standard (or Wi-Fi 4 as it’s known nowadays), first commercially available in 2009. Things were still simple then, and dual-band routers came into existence because we needed them.

Indeed, initially, Wi-Fi started with only the 2.4GHz frequency band, which was, and still is, too ubiquitous. Besides Wi-Fi devices, cordless phones, Bluetooth gadgets, and home appliances (like microwaves) also use this frequency. It’s saturated.

Available to too many applications, 2.4GHz generally suffers heavily from interferences. Soon after the introduction, it quickly proved unreliable for Wi-Fi in urban areas and has remained that way.

That’s when the 5GHz came into play. For the most part, this frequency band is dedicated to the use of Wi-Fi and has a much higher wireless speed.

5GHz was available in 802.11a Wi-Fi standard for a short period as a single-band solution that could even slowly replace 2.4GHz. But due to its shorter range, the then not-so-fast speed, and the fact that there were many 2.4GHz-only clients, 5GHz couldn’t manage to survive on its own — nobody wanted a 5GHz-only router.

As a result, starting with Wi-Fi 4, we’ve always had the dual-band concept: The co-existence of 5GHz and 2.4GHz. A dual-band Wi-Fi router delivers both performance and backward compatibility. Everyone is happy.

Tri-band in Wi-Fi 6E: It’s the new dual-band

Speaking of compatibility, 2021 comes with Wi-Fi 6E. This extension of the latest Wi-Fi 6 standard has a brand-new 6GHz frequency band.

And just like the move from single band to dual-band that took place more than a decade ago, now we’re doing the same, except it is a move from dual-band to tri-band, as a necessity.

That’s right. A Wi-Fi 6E device will need to have these three bands (2.4GHz + 5GHz + 6GHz) to work with all Wi-Fi devices, new and old. And that’s great, except it makes the tri-band notion confusing.

That’s because traditionally, a tri-band router (be it a Wi-Fi 5 or Wi-Fi 6 one) has an additional 5GHz band purely to add extra bandwidth. It does not need this band to work with existing devices.

Keep that in mind for the rest of this post. From here on, the term “tri-band” conveys this type of traditional pre-Wi-Fi 6E routers, namely those with an additional 5GHz band.

Asus GT-AX11000 vs. GT-AXE11000 Routers
Dual-band vs Tri-band Wi-Fi: The GT-AXE11000 (bottom) is one of the first Wi-Fi 6E routers on the market. As such, it’s a new “Tri-band” router compared to the traditional Tri-band GT-AX11000 (top).

Traditional tri-band: It’s all about the extra bandwidth

To understand the idea behind the tri-band, we first need to know how a router’s bandwidth works. The Asus RT-AX89X, for example, is a Multi-Gig Dual-band AX6000 router.

Multi-Gig because it has two 10Gbps network ports (in addition to a load of Gigabit ports). AX is short for the 802.11ac standard (or Wi-Fi 6). And 6000 is the rounded combined bandwidth of the router’s 4800Mbps speed on the 5GHz band and 1148Mbps on the 2.4GHz band.

Since a Wi-Fi client can only connect to a router using one band at a time, the best wireless connection you can get out of the RT-AX89X is 4800Mbps. (That is when we have a 4×4 client.)

But that’s only when there’s just one client. If you have two clients connecting and being active simultaneously, each gets only half of that bandwidth. If you have ten simultaneously active clients, each now connects at around 480Mbps; or 48Mbps if you have 100 clients.

The real-world speeds are always much lower than that. And this started with Wi-Fi 4 that has a much lower ceiling speed per band than Wi-Fi 6.

Here comes an additional 5GHz band

To increase the bandwidth, in 2014, chip makers decided to add another 5GHz Wi-Fi band by splitting the 5GHz spectrum into two groups — upper channels and lower channels — and give one to each. And with that, we have tri-band broadcasters.

A traditional tri-band router includes two 5GHz bands and one 2.4GHz band, or 5GHz + 5GHz + 2.4GHz. In other words, it has double the bandwidth on the 5GHz frequency, compared to a dual-band (5GHz + 2.4GHz) router.


Channels allocation on the 5GHz frequency band, DFS vs Non-DFS

Generally, a dual-band Wi-Fi broadcaster has two distinctive sets of channels. One belongs to the 2.4GHz band and the other to the 5GHz band.

Depending on your locale and hardware, the number of available channels on each band will vary.

This post takes the perspective of the U.S region. Here, the 2.4 GHz band includes 11 useable channels (from 1 to 11) and has been that way since the birth of Wi-Fi.

On the 5GHz frequency, things are a bit complicated — we have DFS and regular (non-DFS) channels. (DFS channels can be problematic and are the main reason we now have Wi-Fi 6E.)

Here is the breakdown of the channels on the 5GHz frequency band (in the U.S.):

  1. The lower part of the spectrum includes channels: 36, 40, 44, and 48.
  2. The upper part includes channels: 149, 153, 161, and 165.
  3. In between the two, we have the following DFS channels: 52, 56, 60, 64, 68, 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144.

In a dual-band (2.4GHz + 5GHz) broadcaster, the 5GHz band gets all the channels above (#1,#2, plus #3 if it supports DFS.)

In a traditional tri-band broadcaster (2.4GHz + 5GHz + 5GHz), the first 5GHz band (5GHz-1) will get the lower channels, and the 2nd 5GHz band (5GHz-2) get the upper channels. If the broadcaster support DFS then the 5GHz-1 gets up to channel 68, and the rest (100 and up) goes to 5GHz-2.

The splitting of the 5GHz spectrum ensures that the two bands do not overlap each other, which would cause interferences. As a result, the total number of 5GHz channels remains the same in a tri-band broadcaster, but each channel has more bandwidth.


A traditional tri-band router supposedly has double the bandwidth on the 5GHz frequency compared to a dual-band router of the same grade. And networking vendors love this. A higher number means a better marketing tool.

Extra on router bandwidth: Wi-Fi vs Wired

It’s worth noting that the real-world Wi-Fi speeds are much lower than that of the standards.

For example, typical 2×2 Wi-Fi 6 (at 80MHz) connection might have a negotiated speed of 1200Mbps. But in my testing, the sustained rate registered around 800Mbps, at best.

That’s because using radio to transmit data, Wi-Fi is susceptible to interferences and therefore has a lot of overheads.

And that’s why wired connections are generally superior in terms of throughputs. A Gigabit connection via a network cable has a sustained speed of almost 1000 Mbps.

In other words, the net rate of a wired connection is about the same as its ceiling speed. The wires inside a network cable are shielded from the elements and can work unhindered.

Also, in a router (or switch), the network ports don’t share the bandwidth. Each port delivers its total rated bandwidth even when all of the ports are active. So, if you copy data from one Gigabit device to another, the speed between them is still 1 Gbps.

But wired networking has one major disadvantage: you need to use wires. And that alone means it can’t beat Wi-Fi.

Dual-band vs tri-band Wi-Fi: The reality

As far as I know, the first tri-band router is the Netgear R8000 Nighthawk X6 that came out in 2014. I remember reviewing it in my past life and having difficulty figuring out how to demonstrate the need for the second 5GHz band.

Frustrated yet curious, I got one for my personal use and ended up putting it in storage without ever figuring out the advantages of the additional 5GHz band. I still have that router today.

Netgear R8000 Nighthawk X6 router
Dual-band vs Tri-band Wi-Fi: Here’s my Netgear R8000 Nighthawk X6 router straight out of storage. It’s one of the first tri-band routers on the market.

And that’s just the way it is. In real-world usage, you’ll probably see no difference between dual-band vs tri-band in standalone Wi-Fi routers. The first reason is that chances are you don’t have that many active clients anyway.

Connected clients vs active clients

As mentioned above, a router shares its Wi-Fi bandwidth between active devices. You can have hundreds of connected clients but only the active ones that count.

The faster a Wi-Fi connection is, the shorter a client remains active — it needs less time to finish transmitting the same amount of information.

For example, as you’re reading this, likely, your computer (or mobile device) is no longer active since it has fully downloaded the webpage. So, in a typical home, chances are you’ll have just one or two active clients at any given time.

And even when you have lots of active clients, how taxing they are on the Wi-Fi pipe also depends on their tier of Wi-Fi, the application they use, and the Internet speed.

Wi-Fi tiers

The numbers I mentioned in the RT-AX89X example above were of top-tier Wi-Fi 6 clients. In most homes, though, chances are you’ll use clients of different Wi-Fi speed grades and standards.

For example, if you use a 2×2 Wi-Fi 5 client, its speed already caps at 867 Mbps, even when it’s the only connected client. If you use 2×2 Wi-Fi 4 devices, this number is now 450 Mbps at most. So on and so forth. Also, some clients use the 2.4GHz band and put no load on the 5GHz frequency at all.

So, not all active clients use the max amount of bandwidth available at the router’s end, even when working at capacity.

Applications

And Wi-Fi clients tend not to work at capacity. That’s because most applications only need a certain amount of bandwidth. You can make more available to them, but that won’t translate into a better user experience. It’s the law of diminishing returns.

Take movie streaming, for example. A 4K stream requires 25 Mbps and won’t use more than that. So the RT-AX89X router’s 5GHz band alone can theoretically handle some 200 Wi-Fi concurrent clients streaming 4K content. Add another few dozen clients on the 2.4GHz band.

The actual number of possible simultaneous streaming clients is fewer in real-world usage, but still, any dual-band Wi-Fi 6 (or even Wi-Fi 5) router can deliver a lot more than a small household would ever need.

Internet speed

The broadband speed is likely the main factor that renders tri-band overkill. That’s because we use Wi-Fi mainly as a bridge to the Internet. And since Wi-Fi and Internet are two different things, faster Wi-Fi doesn’t necessarily translate into speedier Internet access.


• This test transfers data between your device and Ookla test server.

Click the Go button above and do a test right now, and you’ll get an idea of how fast your Internet currently is. (If you want to make sure, check out this post on how I conduct Wi-Fi and Internet testing.)

Let’s say your broadband is 150 Mbps, which is quite decent. When you have ten Wi-Fi clients accessing the Internet simultaneously, using the same application, each of them will be allotted 15 Mbps.

And even if you have just one client, 150 Mbps is still much lower than how fast Wi-Fi can be in general. That said, no matter how much more bandwidth you add to your Wi-Fi, you can’t access the Internet any faster.

The point is, chances are the broadband connection will be used up way before you have to worry about your local Wi-Fi’s speed. Consequently, getting more Wi-Fi bandwidth doesn’t do anything other than making you a bit poorer.

When a tri-band router is useful

There are few instances where a tri-band router makes sense.

First, you need to have many 5GHz clients even think of using a tri-band router. And then, make sure you have at least one of the following to make the investment worthwhile.

Asus RT AX92U 2 Pack
Dual-band vs Tri-band Wi-Fi: The Asus RT-AX92U is a tri-band Wi-Fi solution that transcends Wi-Fi 5 and Wi-Fi 6 standards.

Wireless mesh setup

Wireless mesh is by far the best use of tri-band.

But first, let’s make sure we’re on the same page about what a wireless mesh system means. That’s when you use multiple hardware broadcasters that link to one another wirelessly. In other words, you don’t use network cables to hook them up.

In this case, generally, a tri-band system will dedicate one of the two 5GHz bands as the dedicated backhaul, which has the sole job of linking the broadcasters, leaving the other two bands (the other 5GHz + 2.4GHz) free to serve clients. Among other things, this setup helps reduce or even eliminate signal loss.

It’s important to note, though, that using a network cable to link broadcasters is by far the best way to get a non-compromising mesh system. In this case, you only need to use dual-band broadcasters. Getting a tri-band system with wired backhauls can be wasteful since you still might not use one of its 5GHz bands at all.

Keep in mind that this post talks mostly about standalone routers. While many routers from Asus or Synology can work as members of a mesh system, most standalone routers can’t. They only work as a standalone broadcaster. To these, the mesh motion is irrelevant.

A super-fast broadband connection

If you have a Gigabit-class broadband connection, then a tri-band router can also be fitting in maintaining the high broadband speed to more clients simultaneously.

But, again, keep in mind that online applications generally require only so much bandwidth to work well —  much less than 1Gbps in most cases. The only time faster is always better is when you download a large file.

Compatibility

You can set one 5GHz band to support top speeds and the other band to work in compatibility mode for legacy clients. It’s helpful when you have clients of multiple Wi-Fi tiers or standards.

Heavy local Wi-Fi network usage

A tri-band router is also helpful if you have an extensive network that uses Wi-Fi instead of wired connections for local tasks. It allows for more local bandwidth.

Examples of these include network backups, file sharing, photo/video editing. Another thing is if you use Wi-Fi to connect virtual reality headsets, a dedicated 5GHz (or 6GHz) band sure will help tremendously.

In this case, make sure all clients use the fastest Wi-Fi tier.

The takeaway

As you might notice by now, in Wi-Fi for general usage, you don’t need any additional band in a standalone broadcaster. In some cases, this extra band helps, but still not a must-have. A router with one band for each frequency will always suffice.

On the other hand, I don’t see any instance having more bands — that use different parts of wireless spectrums — would hurt.

So, in the end, it comes down to cash. If you can afford it, go ahead and proceed with a router with the most bands. It’s always nice to be able to turn things up to eleven.


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