Over the last generation of computing, there has been an explosion of devices that no longer have or need the capability of connecting to a hard-wired Ethernet connection, and that trend shows no intention of slowing down. When Personal Computers first started to utilize wireless Network Interface Cards (NICs) they would almost always be the sole device on the network. Fast forward to today, and practically every home has multiple devices, if not dozens, where the devices communicate using radio waves, either over a cellular connection, or over a home wireless network featuring Wi-Fi.

In the PC space, which is the focus of this article, cellular connectivity certainly exists, but almost exclusively in niche roles. While there are advantages to offering directly cellular connection on the PC, the extra recurring cost, especially in North America, means that most laptop owners will use Wi-Fi for network communication.

The term Wi-Fi is something that is omnipresent today, but if based on the Wi-Fi Alliance and adoption of IEEE 802.11 standards for local area networking over wireless. Although the Wi-Fi Alliance has recently renamed their standards, Wi-Fi has in the past been named directly based on the 802.11 standards as follows:

In an effort to simplify branding, the latest three standards of 802.11n, 802.11ac, and 802.11ax have been rebranded to Wi-Fi 4, Wi-Fi 5, and Wi-Fi 6, respectively. In the long term, the new branding should be much easier for most people to grasp, since larger means newer, although we’ve already got some confusion with Wi-Fi 6E – the 6GHz band addition for Wi-Fi 6 – so we shall see how that goes.

One of the many Wi-Fi 6 routers announced at CES 2019 - TPLink AX1800

Today, most homes should have at least Wi-Fi 4, or what used to be 802.11n. After all, this standard came along in 2009. Many will even have Wi-Fi 5, or 802.11ac, which offers some speed upgrades and a few optional extra features to help with scaling. Wi-Fi 6, or 802.11ax, is a very new standard, and until the end of 2019 there were not even that many devices which could connect over it. So, what is the point of this new standard, and do you really need to upgrade your home network?

This article intends to help answer those questions, as well as show how we at AnandTech are transitioning to Wi-Fi 6 for future reviews.

Wi-Fi 6: What’s New

With each successive new Wi-Fi standard, there are almost always improvements to the wireless speed and latency, and that continues with Wi-Fi 6, but the latest standard also improves power efficiency, and likely most importantly, helps address some of the typical issues with Wi-Fi in very crowded environments.

Let’s start with the last point, since it is arguably the most important. As Wi-Fi has become ubiquitous, and as the number of connected devices has grown, one of the biggest issues it has become susceptible to is overcrowding of the spectrum, which can cause even the best networking equipment to slow to a crawl. This is especially obvious in dense urban environments, or stadiums, or theme parks and the like.

What’s your frequency, router?

Only a few years ago, even mid to high tier laptops would ship with just 2.4 GHz 802.11n (Wi-Fi 4) network adapters. If they were to be used in a dense apartment complex, the resulting performance would be abysmal. Moving to the 5 GHz range provided some temporary relief, partly because of the reduced range of the 5 GHz signal, meaning neighboring access points would be less likely to interfere, but also due to 5 GHz offering significantly more channels. 2.4 GHz can only provide a maximum of three non-overlapping channels, but depending on the regulations of each country, there are a total of fourteen total channels, each being 22 MHz wide, but offset by only 5 MHz, so channels side by side will interfere with each other. On the 5 GHz side, there can be up to 23 channels, and none of them overlap.

5 GHz Channel Use in my home

If you needed range, 2.4 GHz was still your best bet due to the attenuation of the 5 GHz signals through solid objects like floors and walls, but in a dense environment, 5 GHz was practically a must-have for any wireless communication.

2.4 GHz Channel Use in my home

But even the 5 GHz space is now getting stretched to its limit, so the Wi-Fi Alliance has added some features to address the crowded spectrum directly. One of the major additions to combat this is Orthogonal Frequency-Division Multiple Access, or OFDMA, which breaks the spectrum into time-frequency resource units, which are coordinated by the access point. These resource units can be allocated to multiple connected devices, allowing them to transmit over the same channel at the same time, as long as the total bandwidth does not exceed the channel width. Previously, every transmitting device would occupy the entire channel for the entire time it was transmitting, so if multiple devices were competing, they would have to wait their turn using Time-Division Multiple Access, where each device would be given a slice of time to transmit. OFDMA spreads out channels to many clients, which can be very beneficial, especially if no single device requires all of the available bandwidth. In addition, Wi-Fi 6 allows for dynamic fragmentation of the packet size, allowing the device to fill available resource units with smaller packets, unlike previous Wi-Fi which required a fixed packet size.

Another interesting trick the Wi-Fi Alliance has added to combat crowding of the spectrum is Spatial Frequency Reuse, which allows devices to figure out if signals that are being transmitted are part of their network, or part of a neighboring network. This means that, for example, two people in an apartment complex were both using Wi-Fi 6 access points and devices, the devices connected to their own access point would be able to read a marker on the channel transmission and determine if that transmission is on their network or not. If it is not, and if the power levels are sufficiently low, the wireless device would be able to also transmit on the same channel at the same time. The devices would adapt their power levels for transmission to avoid them actively interfering with each others’ transmissions.

In addition to this, Wi-Fi 6 also adds an additional network allocation vector (NAV) which should help prevent packets being reset by overlapping networks.

Even with these changes, the Wi-Fi Alliance knows that there is still only a fixed amount of bandwidth even in the 5 GHz range, and as such 6 GHz support is already in the specification, although it will be limited to devices labeled as Wi-Fi 6E, to keep things at least a bit confusing.

A Bonding Moment – Doubling Down on Performance

Although the nominal channel bandwidth for Wi-Fi is 20 MHz, the Wi-Fi specifications have allowed for bonding of multiple channels together to provide higher performance channels. Wi-Fi 4 allowed for 40 MHz channels, and Wi-Fi 5 allowed for 80 MHz and 160 MHz, although the latter was optional, and we didn’t really see it in the PC space until recently. Because it was not a requirement, many Wi-Fi 5 access points and routers did not support it, even if you had one of the most recent wireless adapters which even offers 160 MHz support. Wi-Fi 6 supports the 160 MHz channel width, so we should see more devices adding support. But a drawback of bonding is that it requires concurrent channels to function, and with a limited number of channels, if you had a lot of interference on one channel, it could cause issues. This has somewhat been addressed in Wi-Fi 6 with “80+80” bandwidth, which means that the 160 MHz bonded channel can be made up of two different sets of 80 MHz channels. This was again available in the previous spec, but optional.

To further increase performance even further than just wider channels, Wi-Fi 6 also adds support for an even higher level of Quadrature Amplitude Modulation (QAM), from 256-QAM in Wi-Fi 5, to 1024-QAM in Wi-Fi 6. This moves from 8 bits per tone to 10 bits per tone, allowing more data to be transmitted over the same channel bandwidth. This means that a single 1x1 20 MHz channel can transmit at a maximum of 143 Mbps, and on a typical laptop with a 2x2 Wi-Fi adapter on 160 MHz channels can connect at 2.4 Gbps. The same 2x2 solution on a typical Wi-Fi 5 access point with the typical 80 MHz channel width offers just 867 Mbps, so the jump in performance for Wi-Fi 6 is significant.

16-Level QAM - By Chris Watts - Own work, CC BY-SA 3.0, Link

In addition, Wi-Fi 6 adds in support for Multi-user Multiple-input and Multiple-output (MU-MIMO) to the uplink connection as well, where Wi-Fi 5 only offered it on the downlink side.

Do I need it?

The eternal question with networking is when is a good time to upgrade, and do the latest and greatest additions to the specification provide tangible benefits right now. This is always complicated on Wi-Fi by a lag between access points or routers and devices, and what the upgrade cadence is. Wi-Fi 6 is new enough that many people may not own devices that even support Wi-Fi 6, so upgrading to a new router or access point without devices supporting the new Wi-Fi 6 standard will mean that your devices are still leveraging Wi-Fi 5 or below, meaning there isn’t really a good reason to jump. If you are in the market for a new router or access point anyway though, clearly it is in your best interest to get the latest specification of the standard.

Where Wi-Fi 6 is going to add real-world benefit though is in a couple of scenarios. If your wireless spectrum is very crowded due to being in a dense urban environment, Wi-Fi 6 makes some significant upgrades to its networking stack to help address just that type of use-case. In addition, if you’ve got dozens of devices fighting over Wi-Fi, it may make sense, although the best benefits are achieved when both the access point and client are utilizing Wi-Fi 6.

Performance is also dramatically increased over Wi-Fi 5, so clearly in performance-bound scenarios, the upgrade may be worth the investment, although the tricky part about Wi-Fi 6 is that for the most common 2x2 scenario, where there are two transmit and two receive channels, Wi-Fi performance finally surpasses that of the typical Gigabit Ethernet that most people have in their homes, so although the performance will still be higher than Wi-Fi 5, Gigabit may be a bottleneck, and if so, additional networking equipment may be necessitated. There has been some movement on the multi-Gigabit Ethernet for the consumer, but less than we’d have expected at this point, so Wi-Fi to Wi-Fi may be the least-expensive option for best performance.

The 2020 AnandTech Wi-Fi Test Bed

We’ve been comfortably using Wi-Fi 5 for some time now, and it is only in the last several months that laptops have been shipping with Wi-Fi 6 based networking, mostly thanks to Intel’s Project Athena which has a requirement of the Intel AX200 Wi-Fi module, which is Intel's first Wi-Fi 6 based module on the market. Previously almost all shipping laptop computers offered Wi-Fi 5, and even a few with the latest Intel wireless adapters such as the Wireless-AC 9260 offered the advanced Wi-Fi 5 options such as 160 Mhz channel width, and MU-MIMO, so its nice to see a move to a new standard which includes these benefits across the board.

Although there are now quite a few Wi-Fi 6 routers and access points on the market, we had some specific criteria to meet. The router had to support Wi-Fi 6, and the 160 MHz channels, but because we are testing for performance, and not for capacity, we need an access point with a multi-Gigabit Ethernet connection. A typical laptop with a 2x2:2 network connection will be connecting to the access point at 2.4 Gbps, so transferring files from Ethernet over Gigabit will be a bottleneck. This does limit the selection somewhat.

After evaluating several models, we decided on the ASUS ROG Rapture GT-AX11000. The name is a mouthful, but meets all of our criteria and more. Most importantly, it offers the coveted 2.5 GbE port.

The ASUS ROG Rapture GT-AX11000

As the name implies, this router from ASUS can support up to 11000 Mbps over wireless, thanks to the 4x4 2.4 GHz, offering 1148 Mbps, and the two 4x4 5 GHz networks each offering 4804 Mbps. This adds up to just under 11000 Mbps, although with wireless the maximum connection speed is pretty much impossible to achieve. With the two separate 5 GHz networks, you can easily split off your consumption devices with higher priority devices, reducing interference on each network.

On the Wide Area Network (WAN) side there is a single 1 Gbps connection, and on the Local Area Network (LAN) side there are four 1 GbE and the single 2.5 GbE connection.

This router is built for capacity, with eight external antennae, and being a gaming router it also offers plenty of RGB lighting options. For those that don’t need the lighting, it can be turned off. ASUS also some tools to change the priority of gaming packets to reduce latency, assuming your network is that busy, and specifically prioritizes traffic from other ROG devices to make setup as easy as possible. ASUS even includes a utility to ping the various game servers for popular multiplayer games to provide you a map of latency to each one.

The GT-AX11000 also integrates with the ASUS AiMesh networking equipment to provide a whole-home mesh network, if even a router of this size can’t cover the entire house, either due to size or building materials blocking the signal.

For testing, the router is used in the access point mode, with the LAN connecting being over the 1 Gbps Ethernet, and a server connected directly to the router in the 2.5 Gbps port.

Performance

In order to achieve maximum performance, the latest Wi-Fi 6 standard leverages 1024-level QAM, but depending on the signal strength and quality it will scale down as needed, so to achieve the best performance very high signal to noise ratios are going to be required. Since 5 GHz is attenuated dramatically when it has to go through walls, if you need maximum Wi-Fi performance be aware that you are going to want your wireless router as close to the end device as possible. Luckily that is not an issue in our case, since the router is in the same room when testing for maximum performance, but we’ll also evaluate it in less than ideal scenarios as well.

Wi-Fi 5 vs Wi-Fi 6 – Close AP

First up we’ll test the TCP performance when the Access Point is in the same room as the client.

The performance advantages of Wi-Fi 6 are clear. With the access point in the same room, the SNR is very good and the new 802.11ax standard can really shine. With 1024 QAM and 160 MHz channels, the performance is over twice as fast as the outgoing Wi-Fi 5 with 256 QAM and 80 MHz channels. It is very impressive to see a typical 2x2:2 connection well over the Gigabit barrier, and even though the AX200 network card is the first generation, Intel has already done a fantastic job tuning it. The theoretical maximum transfer rate with 160 MHz channels and 1024 QAM is around 1200 Mbps per connection, so a 2x2 can in theory hit around 2.4 Gbps, meaning there's still room for improvement. Since 802.11ax also can be used on the 2.4 GHz frequency, unlike 802.11ac, the same test was also done on 2.4 GHz, and the results were disappointing. 2.4 GHz can still offer 40 MHz channels, but it doesn’t seem like the AX200 could take advantage of any of that. For reference, the wireless adapter in the laptop was reporting -21 dBm, which is a strong signal, which makes sense since the AP is almost right next to the laptop.

Wi-Fi 5 vs Wi-Fi 6 – Reduced Signal

Moving the laptop further away, and adding several walls and doors in the way to attenuate the signal, the same scenarios were again tested.

With some walls in the way, 5 GHz gets attenuated quite dramatically, and the SNR in the second location was -78 dBm. With such a low signal, the Wi-Fi 6 connection wasn’t able to take advantage of the 1024-level QAM and would have had to drop down to a much lower set, reducing the number of bits per tone, and even though the total channel bandwidth was still 160 MHz, it was only marginally faster on 802.11ax than 802.11ac 80 MHz. 2.4 GHz is not as impacted by walls, and as such was able to maintain the same transfer rate, even though it was still quite a bit slower.

So the results are clear. Wi-Fi 6 can offer a significantly higher level of throughput than Wi-Fi 5, but in order to do so, it needs a strong signal. The Wi-Fi 6 still outperformed the Wi-Fi 5 in the second test with an attenuated signal, but the performance gain was minimal. 2.4 GHz still offers the best signal strength, and therefore would be able to connect further away, and through more obstacles, but doesn’t offer anywhere near the performance of the 5 GHz range. It will be interesting to see the Wi-Fi 6E devices with 6 GHz support when they launch. It will open up Wi-Fi to a wider set of frequency choices, but will offer even less range.

To The Future

If the question is do you need Wi-Fi 6, the answer is most assuredly “maybe”. The performance improvements are substantial, but really rely on a very strong signal to get the most data throughput. Most of the new features of Wi-Fi 6 focus on the influx of devices to the standard, and dealing with many devices connected to the same access point, or devices trying to share spectrum when connected to different access points.

The addition of Orthogonal Frequency Division Multiple Access to the Wi-Fi 6 standard will likely be the most impactful change to this revision. It will allow access points to carve up their channels into smaller slices, allowing more devices to communicate at the same time with less overhead. Each device will lose out on peak throughput, but the reduced latency should help a lot, especially in very dense environments. It should help with excessive overhead on the network layer when multiple devices are sending many small packets at once, which is a very common scenario, especially in an office or stadium situation.

Multi-User MIMO was in the Wi-Fi 5 specification as an optional implementation, and as such it did not really take off. Wi-Fi 6 should make this more prevalent, and also adds support to the MU-MIMO on the uplink, not just the downlink side. This will increase the capacity of access points for higher-speed use cases, but MU-MIMO did not get a lot of traction in Wi-Fi 5 so we will have to see how much adoption it gets in Wi-Fi 6.

The wider 160 MHz channels will offer significantly more throughput in the home environment, as we saw in our performance tests. As with the 1024-level QAM though, to see the biggest benefit you will need a strong signal. The vast majority of home networking is still limited to 1 Gigabit Ethernet, which puts Wi-Fi 6 into somewhat of an awkward spot, since it can transfer faster than most wired home networks, but even so, that is still a significant improvement over Wi-Fi 5 which would cap out around 600 Mbps on the best Wi-Fi adapters. If you work with a lot of large files, and you prefer to use Wi-Fi instead of the more consistent, yet cumbersome Ethernet, there’s still a nice boost to be had.

The future looks strong for Wi-Fi, and the Wi-Fi Alliance has made some excellent revisions to their standard to help improve Wi-Fi for the next generation of devices. As with any standards change, the impacts will not be seen right away. Both the access point, and the client need to be leveraging the new standard for the improvements to be noticeable. We’ve already seen the latest generation of smartphones start to offer Wi-Fi 6, and there’s been some movement in the PC space as well with Intel’s Project Athena. Anyone looking at a new router today should certainly opt for a Wi-Fi 6 model, but there’s likely not a major need for most people to move from Wi-Fi 5 access points right away. If you live in a heavily congested wireless area, the advantages of features like BSS coloring and Spatial Frequency Reuse should help out in those scenarios, but for people looking at purely performance, Wi-Fi 6 somewhat runs into a wall of its own making, since it can now transfer at over Gigabit speeds on a typical 2x2:2 connection. But who are we to question performance?