The ARRIS SURFboard S33 DOCSIS 3.1, first announced in November 2020, sure is an interesting Multi-Gigabit cable modem.
For one, it’s super cute, at least compared to the squarish design found in previous ARRIS SURFboard modems. And then, it can handle up to 2.5Gbps of broadband speeds and two static IP addresses.
Similar to the case of the Netgear CM2000, the SURFboard S33 is probably not a great choice for those having a sub-Gigabit internet connection.
For a download speed slower than 300Mbps, consider a DOCSIS 3.0 modem instead. Else, it’s not money well-spent.
But if you have (close to) Gigabit or faster cable broadband, or want to stay future-proof, this modem is an excellent buy.
Indeed, with a $200 price tag, the ARRIS S33 is a more sensible investment than the pricier Netgear counterpart. Make sure, though, that you have a Wi-Fi router that has a matching WAN speed.
Dong’s note: I tested the ARRIS SURFboard S33 with a Comcast cable plan. While the modem works with almost all cable Internet providers in the U.S., the information expressed here typifies an Xfinity experience.
ARRIS SURFboard S33: A little modem with big options
I had a little pleasant surprise when taking the ARRIS SURFboard S33 out of its packing.
The modem was much smaller than the photo suggested. Indeed, it’s the most compact Multi-Gig modem I’ve seen, measuring just 5.14 x 1.8 x 4.74 in and weighing in less than a pound.
A typical cable modem at hearts
On the inside, though, the S33 is a typical DOCSIS 3.1 cable modem. It comes with a service coaxial connector and two network ports. One is a 2.5Gbps Multi-Gig port, and the other is a standard Gigabit port.
This is where it gets interesting. Here’s how you can use these ports:
- One at a time at their max speed:
- 1Gbps port for a Gigabit or slower broadband connection.
- 2.5Gbps port for a Gig+ or faster connection, up to 2.5Gbps of download speed. (This port is compatible with sub-Gigabit plan, too.)
- Two at the same time if you have a connection that includes two static IP addresses.
Unfortunately, the ARRIS SURFboard S33 doesn’t support WAN Link Aggregation. Specifically, you can’t use both of its network ports to deliver a 2Gbps connection. For that, you’ll need to use the SB8200.
That said, the table below shows how the S33 differentiates from its older cousins.
ARRIS SURFboard S33: Hardware specifications
|Max Download Speed
|Up to 2.5Gbps and 1Gbps
|Up to 686 Mbps
|Up to 1 Gbps
|Up to 2 Gbps
|DOCSIS 3.0 Specs
(Downstream x Upstream Channels)
|32 x 8
|16 x 4
|32 x 8
|32 x 8
|Applicable Cable Internet Speed Plan
|Built-in Wi-Fi Gateway
|5.14 x 1.8 x 4.74 in
|5.25 x 2.17 x 5 in
|7.15 x 4.5 x 6.11 in
|5.13 x 1.7 x 5.25 in
Like all DOCSIS 3.1 modems, the SURFboard S33 can function as a top-tier DOCSIS 3.0 modem.
Keep in mind, though, that you should use it as such only when you have a download speed of around 400Mbps or faster. That’s because certain low-speed cable plans require a DOCSIS 3.0 modem to work.
On top of that, the S33 is designed to work with a Wi-Fi 6 router, preferably one with a Multi-Gig WAN port. If you have an aging Wi-Fi 5 router, it might be a good idea to upgrade it or stick with a DOCSIS 3.0 modem.
ARRIS SURFboard S33: Detail photos
Cryptic status light
Unlike most cable modems, including older SURFboard models with multiple status lights, the S33 comes with a single large LED light on the front. This light changes its color to show the modem’s conditions.
Specifically, it has three colors:
- Amber means the modem is off. This is the color of the plastic.
- Green means the modem is on and:
- Flashing: A firmware update is in process. (Make sure you leave the modem alone and don’t unplug it.)
- Blinking: Searching for signal. This can means there’s no signal at all.
- Solid: Modem is working in DOCSIS 3.0 mode.
- Blue is only available in solid which means the modem is working well in DOCSIS 3.1 mode.
I’m not too fond of this status light design and find it unnecessarily cryptic. For example, folks can easily mistake flashing for blinking. So, this light sure will make troubleshooting the WAN connection harder.
However, the light did work as intended in my trial, so you only need to remember the specificities above. Hint: stick a note with the information on the side of the modem itself. It’ll come in handy.
Standard setup process
Like other cable modems, the ARRIS SURFboard S33 comes with a web user interface, accessible via the 192.168.100.1 IP address. The default username and password are admin and password. And there’s the ARRIS SURFboard Manager mobile app, too.
However, you need neither for the activation, at least if you use it with an Xfinity cable plan. In my case, everything went the same as I described in this detailed post on how to install/replace a cable modem.
(I did try the app out briefly, and it was quite terrible. It’s a good thing that it’s not necessary.)
Worse comes to worst; you only need to connect the hardware — service port to the service line and one of the modem’s LAN ports to your router’s WAN port. Then call the provider’s support line and give the technician the modem’s MAC address on its underside to have it activated on your account.
The only time using the web interface is necessary is when you have a (business) cable plan, and you want to assign the static IP addresses to the modem’s two ports. I couldn’t try this out since it didn’t apply to my Xfinity account.
Other than that, like the case of other modems I’ve tested, the interface only shows you the broadband connection information, which is only useful when you need to troubleshoot a non-working connection.
In short, it won’t take long for you to install the modem yourself.
ARRIS SURFboard S33: Fast, reliable, and hot
I used the S33 for more than a week and had no connection issue with it.
My Xfinity cable plans caps at 900Mbps download, and the modem delivered exactly that. I had no way to test whether it could deliver more, but I have no reason to doubt that it can.
That said, again, if you have a cable plan that’s Gig+ or faster — but no faster than 2.5Gbps — the ARRIS SURFboard S33 will get the job done, even well done.
One thing to note is that this little device ran a bit hot in my trial. It wasn’t hot enough to cause concerns — at least in my case — but sure hotter than other larger modems I’ve used.
ARRIS seems to have slightly overlooked the potential overheating issue in making the S33 a compact (and cute) device.
As a rule, you should leave the modem (and Wi-Fi router) in an open space with good ventilation. If that’s the case, you have nothing to worry about. On the other hand, if you tend to tuck your stuff away in a tight closet, pick another modem instead.
ARRIS Surfboard S33's Rating
Fast and reliable performance, up to 2.5Gbps of broadband speed
Compact and nice-looking design
Can handle two status IP addresses
Easy to set up
Cryptic, impractical single-status light
Runs a bit hot
Terrible mobile app
No WAN Link Aggregation
For the price point, the ARRIS SURFboard S33 is an excellent cable modem for anyone who has a cable Internet place of 500Mbps download speed or faster.
Just make sure your provider supports it and that you also have a Wi-Fi 6 router plus a well-ventilated spot to place it.