The only differences between the two, albeit big ones, are that the XT8 features Wi-Fi 6 and a multi-gig WAN port. Other than that, they share everything else, the appearance, setup process, features, how they work as mesh systems, and even some shortcomings.
This review focuses on these differences. It's intended for those who have already read my take on the CT8.
In all, compared to the CT8, the ZenWiFi AX XT8 has more than enough to justify the extra $100 you'd need to spend. Though not a must-have, it's a reasonably-priced, flexible Wi-Fi 6 AiMesh system with a ton more to offer than its more expensive rivals.
Asus ZenWiFi XT8: Everything the CT8 has and a lot more
As a mesh system, the ZenWiFi AX, like the CT8, includes two identical routers. From the front, you can't tell the hardware of the XT8 and the CT8 routers apart. The two look the same, sharing the single-slot-toaster design, and are available in white or charcoal colors.
Familiar design, now with Multi-Gig WAN support
On the back, though, you'll note that the XT8's WAN port is now a Multi-Gig port that works either at either 1Gbps or 2.5Gbps. Also, the USB 3.2 Gen 1 port is on the right side instead of the left.
Like the CT8, the XT8 features Dual-WAN -- you can turn its USB port or another LAN port into a second WAN port if you want it to host two broadband connections at a time for load balancing or high availability.
By default, there's no Multi-Gig LAN port. And that's disappointing since that means locally, the best wired-to-wireless connection you'd get out of the XT8 is 1Gbps.
But when working as a node, the XT8's 2.5Gbps WAN port now works as a LAN port. However, generally, in real-world usage, it's not a good idea to count on the wireless backhaul to reliably deliver the same speed as a wired Multi-Gig LAN connection.
Also, you'll need to have a second node unit before you can see the value of this port. With a 2-pack, the speed is limited by the other Gigabit ports anyway.
High-speed backhaul band, presently no 160MHz channel support for clients
Each XT8 hardware unit is an AX6600 tri-band router with one 2.4GHz and two 5GHz broadcasters. The router dedicates one of the 5GHz bands, the 5GHz-2, as the dedicated backhaul, which works solely to link the two hardware units to form a mesh system.
The 5GHz-2 is the most powerful band, featuring 4x4 Wi-Fi 6 to deliver up to 4800Mbps. It also supports the venerable 160MHz channel width. Thanks to this strong backhaul connection, you can place the XT8's hardware further from each other and still have a fast mesh system.
The other 5GHz band (5GHz-1) uses 2x2 Wi-Fi specifications and generally caps 2400 Mbps for Wi-Fi 6. Unfortunately, however, the XT8's front-haul doesn't support 160MHz channels. As a result, Wi-Fi 6 clients can connect at 1200 Mbps at most in a wireless setup, while Wi-Fi 5 devices will get 867 Mbps.
Update: Asus told me on February 11, 2020, that it
would might release a new firmware update that opens up the front-haul to support 4x4 160MHz specs, effectively doubling the XT8 satellite's Wi-Fi speed for clients. This never turned out to be the case, however.
Wired backhaul support
Like all AiMesh routers, the ZenWiFi AX support wired backhaul -- you can use a network cable to hook one router to another.
In fact, if you have a Multi-Gig switch, it's one of a few Asus broadcasters that supports Multi-Gig backhauls. But there might be a catch.
Extra: Important note on using wired backhaul
Since the XT8 is purposely built for a wireless setup, its firmware might not be tuned for a wired backhaul setup. As a result, new firmware might cause issues if you use wired backhaul with it.
Generally, in my experience, if your (wired) network is stable, it's a good idea not to upgrade the firmware right away but only after the subsequent version of the new version is available.
In other words, a new major upgrade tends to include issues that need to be ironed out by a minor version. If you're aware of this, then it's OK to use this mesh with wired backhauls.
In a wired backhaul setup, by default, the XT8's 5GHz-2 band is still not available to clients -- it remains a hidden dedicated backup backhaul in case the wired connection is lost.
So, when you use SmartConnect, this 5GHz-2 band is not part of the main Wi-Fi network. In short, it will not be available to clients at all.
There's a way to make use of this band, however. You can manually create a new unhidden SSID with it, different from the primary Wi-Fi network. This SSID will then be available, throughout the AiMesh system, as separate 5GHz-only full 4x4 Wi-Fi 6 Wi-Fi network for clients.
In other words, like all tri-band AiMesh systems, with a wired or wireless backhaul, you'll need to do a bit of tweaking to make the 5GHz-2 band available to clients.
Asus AiMesh and firmware updates
Asus regularly releases firmware updates, a Linux-based operating system called Asuswrt, for its routers. Many of these updates add new features to the hardware -- they do more than patch security vulnerabilities.
Some updates may inadvertently cause a particular model to go haywire, likely because the company tries to do so much with its routers.
As a result, firmware can be a tricky thing with Asus. When it comes to updating -- especially in an AiMesh setup of mixed hardware units using wireless backhauling -- keep the following three items in mind:
- Avoid the initial major release(*): This is the first firmware version of a model where the 3xx number changes, such as from 384 to 386 or from 386 to 388. Generally, the latest minor update of the previous major firmware release is always the most stable.
- Avoid using Auto-Update for firmware: You should update the firmware when you see fit instead of letting the hardware update itself.
- Version consistency (in a mesh system): Generally, it would be best to use the firmware version of the same major release for all AiMesh members. (Mixing hardware of different releases might produce mixed results.)
(*) How to read an Asus router's firmware: As shown in the screenshot below, in a particular official firmware version, such as 22.214.171.124.386_47629, the 3xx number in the middle denotes Asus's home-grown major release. The following number -- often includes five digits, such as 47629 in the screenshot -- indicates a minor update.
(A firmware version that starts with 9.x.x.x instead of 3.x.x.x is a beta release meant for testing purposes only.)
The part before that -- 126.96.36.199 in the screenshot -- is the Linux kernel version that will also change, albeit much less frequently. It's even more significant and should also be taken into consideration.
On the one hand, moving between major releases might break your AiMesh setup or even your standalone router. On the other, new hardware comes with a specific initial version out of the box -- you have no option to downgrade it -- and some old models won't get the latest release. So depending on the mesh combo, your luck will vary.
AiMesh started as an add-on feature with firmware version 384 in early 2018 -- represented by the RT-AC86U -- and was stable by the latest minor update of this version. In early 2020, Asus released version 386, buggy in the early stages, to add AiMesh 2.0 via the introduction of the ZenWifi product line. By late 2022, version 386 became fully mature, and Asus started releasing version 388, and the history repeated itself. So on and so forth.
As a rule, in a mesh system, it's best to wait for a few minor updates of a major release before upgrading. Depending on the hardware combo, you might need to rebuild the system from scratch or reset and re-add a satellite node if you change the major firmware version (in one or all hardware units involved.)
ZenWiFi AX XT8: Detail photos
ZenWiFi AX XT8: Hardware specifications
|Full Name||Asus ZenWiFi AX AX6600 Router|
|Dedicated Backhaul Band||Yes (5GHZ-2)|
|Dimensions (WxDxH)||6.29 x 2.95 x 6.35 in |
(16 x 7.5 x 16.15 cm)
|Weight||1.56 lb (710 g)|
|5GHz-1 Wi-Fi Specs||2 x 2 AX: Up to 1200 Mbps|
|5GHz-2 Wi-Fi Specs||4 x 4 AX up to 4800 Mbps|
|2.4GHz Wi-Fi Specs||2 x 2 Wi-Fi 6 up to 574 Mbps|
|Front-haul Channel Width Support||20Mhz, 40MHz, 80MHz|
|Mobile App||Asus Router|
|Web User Interface||Yes (Full)|
|AP Mode||Yes (as a router or a mesh)|
|USB Port||1 x USB 3.2 Gen 1|
|Gigabit Port||3 x LAN|
|Multi-Gig Port||1x 2.5 Gpbs/1Gbps WAN|
|Processing Power||1.5GHz quad-core CPU, |
256 MB Flash, 512 MB RAM
Familiar settings, features, and shortcomings
Again, other than the more powerful hardware, the XT8 shares the same set of settings and features as the CT8. It also uses the same web interface and the Asus mobile app. That said, you can find out more in the review of the CT8, including how to set the system up.
To avoid repeating myself, I'll recap below some significant points.
Asus ZenWiFi XT8’s highlights
- Out of the box, the two XT8 hardware units are pre-synced. No matter how you change them individually -- like using each as a standalone router for a different home -- once restored to default settings, they are ready to work together as a mesh.
- The XT8 router can work with all other AiMesh-enabled routers, as the router unit or a satellite node.
- You can restore the XT8 router with the settings of any previous Asus router, making upgrading an easy job. Note, though, that it's always better to set it up from scratch to avoid potential setting conflicts
- The XT8 can work as a node for a system hosted by any other AiMesh-ready router. Or it can host one to extend its own network.
- There are lots of network settings, enough to make almost any advanced user happy, and features anyone would appreciate. These include AiProtection (online protection and parental control), Traffic Analyser, Adaptive QoS, VPN (client or server), and an excellent Dynamic DNS.
- AiMesh now has a new section of its own, within the web interface, which makes managing and adding additional nodes easier. You can also make use of the XT8's USB port even when it's working as a node.
- The USB port can do all that you can think of for a router peripheral port. You can use it to host a printer, a cellular modem, or a storage device to deliver all storage-related features you can imagine -- data sharing/syncing/streaming, Time Machine backup, PC-less downloading, and more.
Asus ZenWiFi AX6600’s shortcomings
And like other Asus routers, the XT8 shares the same shortcomings, too. First and foremost is the fact it can be buggy. Due to the sheer amount of features and settings, it seems Asus has had trouble keeping tabs on them all.
For example, a firmware update can cause issues -- you might need to reset the system and set it up or restore settings from a backup file to fix it. Like the case of other AiMesh routers, the Guest networking feature was only available at the router unit and not throughout the system during my trial.
(For the latest on AiMesh, check out this frequently updated post.)
On top of that, make sure you understand the inherent risks of using the DFS channels, which is the only option to make the router's 5GHz band work in the 160MHz channel. Hint: Turn this off if you want to make sure your connection is stable.
Other than DFS-related issues, you can expect most of the system's shortcomings to be addressed one way or another via future firmware updates. However, the excessive amount of settings can be overwhelming for home users and might cause the system to remain buggy in some shape or form.
ZenWiFi AX XT8 AX6600: Excellent performance
For the official scores, I tested the ZenWiFi AX in a wireless setup. The system doesn't have the Wi-Fi specs to be the fastest on the market. Instead, it delivers extensive Wi-Fi coverage and still with excellent real-world throughputs.
I used both 2x2 Wi-Fi 6 and top Wi-Fi 5 clients for the testing. Keep in mind that, in the intended wireless setup, the XT8 is a 2x2 system of both standards on its fronthaul.
Fast Wi-Fi speeds
As a mesh router, the XT8 delivered precisely the kind of performance I had expected from it -- hardware without Multi-Gig LAN or 160MHz channel width support.
(The router will deliver better Wi-Fi performance when you use it as a standalone device or open the 5GHz-2 band to clients.)
My Wi-Fi 6 client connected at 1.2Gbps and had a sustained speed of almost 840 Mbps at a close range of fewer than 10 feet (3 m).
When I increased the distance to 40 feet (12 m), it registered higher than 770 Mbps. Wi-Fi 5 clients fared the worst on the chart. However, that's because the XT8 is the only one among the existing handful of Wi-Fi 6 mesh systems on the market that doesn't feature 3x3 or faster Wi-Fi 5.
That said, its scores of some 660 Mbps and 450 Mbps for close and long-range, respectively, weren't bad at all.
The XT8 did it best when working as a mesh. The node (satellite) unit delivered the best performance to Wi-Fi 6 clients, averaging 850 Mbps and 792 Mbps for close and long-range, respectively. These were faster than higher-specced systems.
Excellent range, reliable signals
With two units, the XT8 could cover anywhere between 4000 ft² (372 m²) to 5000 ft² of residential space in my testing with fast Wi-Fi speeds.
I tested the system with the node placed some 40 feet away. But in anecdotal tests, I could put it some 70 feet away and still get speed fast enough to deliver my 300 Mbps internet in full.
Your mileage will vary, but it's safe to say, thanks to the full 4x4 Wi-Fi 6 backhaul, in a wireless setup, the XT8's range delivers. The system proved to be reliable, too. It passed my 3-day stress test without any disconnection.
Real Wi-Fi 6 speed via (buggy) wired backhaul
The XT8's wired backhaul also worked in my trial -- in this case, the distance between the two units doesn't matter much.
I created a separate network with the 5GHz-2 band and was able to get the full 2400Mbps connection speed from it using my 2x2 Wi-Fi 6 clients.
Note, though, that this connection speed was between the clients and the XT8. So, the only time you truly benefit from the Multi-Gig Wi-Fi speeds is when you have a Multi-Gig WAN connection and the clients connect directly to the router.
Since the XT8 has no Multi-Gig LAN port, clients connected to the node won't get real-world speeds faster than 1Gbps. Still, it's nice to have the option to have a 5GHz band working for high-speed clients. Or is it?
Update: Over additional testing, as it turned out, the XT8 might have an issue with the wired backhaul. Again, it seems the system was tuned for a fully wireless setup and a firmware update might cause problems when you use it in a wired setup -- you might need to reset it and set it up again. Though the issue hasn't been consistent, to be sure, it's better to use it in homes that have no wiring.
Decent performance as a mini-NAS server
Without a Multi-Gig LAN port, the ZenWiFi AC XT8 can't compare to those with one in terms of network-attached storage performance when hosting an external drive. But it was much faster than the CT8 in my testing.
When coupled with the SanDisk Extreme portable SSD, via a Gigabit connection, the router scored 46 MB/s and almost 65 MB/s for writing and reading, respectively.
Asus ZenWiFi XT8's Rating
Fast Wi-Fi performance and large coverage at a comparatively affordable cost
Improved and flexible AiMesh
Lots of network settings and useful features, including free real-time online protection for life
Full 4x4 dedicated backhaul band with optional wired backhaul support
Multi-Gig WAN port with Dual-WAN and WAN link aggregation
No 160MHz 4x4 support for Wi-Fi 6 clients in a dedicated wireless backhaul setup
No Multi-Gig LAN port or LAN link aggregation
Only four network ports on each hardware unit
Firmware can be buggy, especially via wired backhaul
Storage performance (when hosting an external drive) could be better
The ZenWiFi AX XT8 AX6600 Whole-Home Tri-band Mesh Wi-Fi 6 System is one out of more than a dozen Asus AiMesh systems I've tested, and it's one of the best, if not the best to date, for those needing a fully wireless setup.
The system is far from perfect, though. It's not the fastest, nor does it deliver all features you can get from an Asus router -- it has no game-specific features or Multi-Gig LAN port. And like most Asus routers, it can be buggy, too. You might need to work at it for a bit before it works for you.
In return, it has an excellent combination of everything you'd look for in a mesh Wi-Fi system, which is fast performance and broad coverage. There's hope that it only gets better via firmware updates.
Most importantly, at less than $450, it's a steal. Many other 2-pack wireless mesh systems on the market, like the Netgear Orbi RBK852 or the Arris SURFboard mAX Pro, cost hundreds of dollars more yet have less in features and network customization.