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ARRIS SURFboard S33 Review: A Solid Multi-Gig Modem with Minor Caveats

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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 Modem and Power Adapter
The ARRIS Surfboard S33 is a cute little cable modem.

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 less than a pound.

The S33 has a new curvy design to match ARRIS Wi-Fi 6 broadcasters, namely the SURFboard mAX Pro and SURFboard mAX. It comes with rounded corners and looks like a piece of decor.

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 a 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

SURFboard S33SURFboard SB6183SURFboard SB6190SURFboard SB8200
Max Download SpeedUp to 2.5Gbps and 1GbpsUp to 686 MbpsUp to 1 GbpsUp to 2 Gbps
DOCSIS 3.0 Specs
(Downstream x Upstream Channels)
32 x 816 x 432 x 8
DOCSIS 3.1-readyYesNoYes
Applicable Cable Internet Speed Plan2.5Gbps400Mbps600Mbps2Gbps
Gigabit Port12
Multi-Gig Port10
Multi-Gig Broadband-readyYesNoYes
Built-in Wi-Fi GatewayNo
Digital Voice-ready
Dimensions5.14 x 1.8 x 4.74 in5.25 x 2.17 x 5 in7.15 x 4.5 x 6.11 in5.13 x 1.7 x 5.25 in
Weight14.4 oz1.5 lbs1 lb 1.59 lbs
(at publication)
ARRIS SURFboard S33 vs. other ARRIS SURFboard modems

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

ARRIS Surfboard S33 Power Adapter
Out of the box, the ARRIS SURFboard S33 comes with a power adapter.

ARRIS Surfboard S33 Front in hand
The new modem is quite compact and cute.

ARRIS Surfboard S33 Backside
On the back, the ARRIS SURFboard S33 includes a 2.5Gbps and a 1Gbps port. You can only use these two ports simultaneously with a cable plan with two static IP addresses.

ARRIS Surfboard S33 Front
The ARRIS SURFboard S33 cable modem's front. Note the status light under the SURFboard logo.

ARRIS Surfboard S33 Underside
The underside of the ARRIS SURFboard S33. Note the MAC address required for manual activation and the ventilation openings.

ARRIS Surfboard S33 Service Port
The ARRIS SURFboard S33's service connector is where you screw a coaxial cable into.

ARRIS Surfboard S33 Front Rigth
The ARRIS SURFboard S33's overall design resembles that of the SURFboard mAX mesh hardware.

ARRIS Surfboard S33 Top
The ARRIS SURFboard S33's top. Note the ventilation grills.

ARRIS Surfboard S33 Next to SB6141
The new and cute ARRIS SURFboard S33 is next to the old and ugly SURFboard SB6141 modem.

ARRIS Surfboard S33 Box
The ARRIS SURFboard S33's retail box.

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:

  1. Amber means the modem is off. This is the color of the plastic.
  2. 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 mean there's no signal at all.
    • Solid: Modem is working in DOCSIS 3.0 mode.
  3. 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.

ARRIS SURFboard S33 Modem Status Light
Here's the ARRIS SURFboard S33 modem's status light in action.

Standard setup process

Like other cable modems, the ARRIS SURFboard S33 comes with a web user interface, accessible via the 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 web interface
The Arris SURFboard S33's web interface.

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

8.2 out of 10
ARRIS Surfboard S33
9 out of 10
Features and Setup
7 out of 10
8.5 out of 10


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.

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40 thoughts on “ARRIS SURFboard S33 Review: A Solid Multi-Gig Modem with Minor Caveats”

  1. I purchased the Arris S33 Cable Modem today (03/25/2024) from at Microcenter for $189. Amazon was $199 (and delivered after 2 business days after they find one). I used the xFINITY app off my phone (after turning WIFI off) to enter the MACID and it all worked just lovely (Blue Light).
    Problems and Comments:
    – xFINITY app worked, but once I had it on their network, I rebooted the cable modem and my main router (ASUS RT-AX88U). Sorry I cannot remember the sequence.
    -My Mesh RT-AC88U was not rebooted. Other PC’s did not need a reboot
    -The doc says (the cable modem address) userid/password is admin/Password….However, the password was the last 8 digits of the serial #.
    -> The S33 replaced a SB8200 which I have had for 5 years. My max download is around 800 and speeds remain about the same (no surprise). However, will speed test more during non-peak work at home times. The main upgrade reason is to be positioned for upgrade speed deals. The neighborhood for xfinity just upgraded to the curb, the infrastructure.

  2. Hi Dong. I replaced a Netgear CM2000 with the S33. I’m using a Synology rt6600ax mesh system.

    With the CM2000 I was able to get to the cable modem’s web interface at via the Ethernet lan

    I am not able do so now at the same address with the s33 on the lan. Nothing has changed in the rt6600ax and routers is same subnet as before

    I am able to of course connect directly to s33 web interface via Ethernet of laptop direct to s33.

    With all being equal to setup before on CM2000 that I could access on Mac via LAN at, and not being able to do so with same address for s33, I can’t figure out why the s33 is not accessible.

    Any thoughts on how to make that work? Thanks!

    • It should work, Alan, unless the IP was changed without your knowing it, such as when done by the ISP. You might just need to restart it and/or the router.

      • Hi Dong

        Thank you for the reply.

        I did try to power down the Synology RT6600AX router and s33, let the s33 come back up with link steady then power up Synology again. No luck

        It’s interesting that nothing was changed in the network other than the modem from cm2000 to s33 which both have the same web interface ip at Cm2000 is addressable on the LAN while s33 is not after change.

        Synology local network ip is set to with a starting ip address of to
        Gateway and primary dns is

        So im assuming that there is some firmware blocking issue in the s33 that is not allowing these different subnets to talk over the LAN to the S33 Wan port? Obviously was not an issue with the CM2000

        I am not sure how to solve this. A port forwarding rule?? If so how to set it up in RT6600AX?

        Any help appreciated. Perhaps you can try it out if you have access still to the RT6600 and S33?

        Thank you!


        • I haven’t tested the RT6600AX with the S33 specifically, but that shouldn’t make a different since you’re reaching the device via its IP address. You can try the ping command to to see what the response is. If it’s not found, then your modem is using a different IP.

          By the way, saying stuff like “I am not able do so now” is quite meaningless in troubleshooting. You must describe what happens when you do something, etc. Don’t treat a tech gadget like your feelings. The point is you need to know how to describe your problem in specificities if you want to find solution.

          • I did try the ping command and am not able to reach

            When you say the Modem is using a different IP do you mean private IP address? The s33 internal web address is stated on the device as

            What should I be checking? Thank you

      • Yeah, it’s in the open and I figured it would be fine. I know some devices just run a little hot but I had a fan available so I thought “what the heck, why not?”.

  3. S33 was in open area, kept overheating and would drop out, disconnect, had 3 service calls from spectrum, paid 200$, called arris told them I measured surface temperature, 125 far. They told me to unplugged it , and would call me back with RA #, cuz their computer was down, bought a new SB8200, and haven’t had any problems since, poor design ventilation, and 3 months of aggravation, after reading reviews, Amazon, Best Buy, etc. Waiting for call back, hope they will send me different model cuz this one is awful, they need to just check reviews, 2 yr warranty, just aggravated with time spent, besides cost.

    • 125F is quite hot, Mark and the modem shouldn’t be that hot. We’ve used a few in a closet, and they never gets hot or warm. Something is not right with the unit.

  4. Will my NETGEAR – Orbi AX4200 be able to take advantage of the s33 if i have a 1gig plan through Xfinity?

    • It’ll work with no problem, Kris, but you will not get the full 1Gbps out of it — you’ll get around 900Mbps at most. (Comcast tends to provision its speed 20% more, so you *might* get 1.2Gbps of actual speed out of the modem.) To get a full Gig or higher, you need a router with a Multi-Gig WAN port, but the benefits might not be worth the investment. More in this post.

      • Very helpful! I currently have a Netgear CM1000 but comcast doesn’t seem to support this modem any longer based on a popup i get when I login. I’ve had a fairly stable connection, though my partner and I have two tablets that video stream (baby monitor) and both do video calls at the same time sometimes for work. My partner has stated that sometimes the internet lags, but most of the time it’s fine.

        Would you upgrade to the s33 if you were in my shoes?

  5. Hello Dong,
    Currently with 1GIG w/Spectrum service 😢 and thier E31T2V1 modem, WRT3200 Linksys Router. Our issue is WiFi signal upstairs and notice getting dropped a lot while PS4 wired and wondering if the SB33 will solve these issues. I know there’s a lot of variables for these options which also may consider the Mesh option with the SB33.

    • You have dated hardware, Robert. And what you’re using is NOT a modem.

      In any case, you can start with a new modem, like this one or one of these, and then one of these routers. A mesh is NOT an upgrade to a router, just FYI — More here.

      Check out the related posts in each of the linked articles for more.

  6. Upgraded from sb8200 to the s33 and ran into a throttling issue with my atlas Max 6e . On a gig plan and it would cut my speed to 500mb through the wired port. Reverted back to the sb8200 and my speeds would go back to 950mb.. changed the router to the tp link deco 75 with the s33 and it would jump up to 950m. Guessing something with the 2.5 gps to 5gps port on the atlas

  7. Thanks for all the info you provide in this website.

    Do you know if this modem has AQM like the Motorola MB8600 and MB8611?

    I’ve also read that all DOCSIS3.1 modems have AQM and another type of latency boosting feature but I can’t remember what it’s called.

    I’m trying to decide between this Arris 33 and the Motorola MB8611.

    • I wouldn’t worry about that, James. It’s handled by the provider and if a modem is accepted, it must support whatever the provider has to offer.

  8. Great post/thread Dong. Juggling between the S33 and MB8611, leaning towards the MB8611 as it’s about $30 cheaper with Amazon pricing currently. Thinking of making the upgrade to the Xfinity 900mbps plan in the coming days/weeks.

  9. I have recently purchased a Netgear 2050v. I also have Comcast gig -1200. This modem will be connected to my Asus rt-ac68u router. Am i not going to be able to receive my 1200 because of the WAN connection on my Asus rt-ac68u. Thanks, Tom Weeks

  10. Hi Dong

    I curious about your thoughts on how to compare the S33 vs your review of the MB8600. I’m also in the Bay Area and am on Xfinity with 1200mbs down/ 40 up service. Trying to make an informed decision about next upgrade. Much appreciated.

  11. I’ve been running the S33 for about 6 months and love it. It’s tied to the ASUS AXE11000 via the 2.5 port and I get excellent throughput. I haven’t had any overheating issues for what it’s worth.

    • Hi would you recommend this Arris S33 or the Motorola MB8611 for Comcast 800Mbs package? I’m struggling to make a choice.
      I was going to get the MB8600, but it’s not on the “official” Xfinity hardware list anymore, and the Netgear stuff requires yo many $$$$

      . Sigh…

      P.S. I just stumbled onto your site. Great stuff Dong! I have a lot to read about.

      Thank you!

  12. I am really curious on your thoughts on the S33 next to the SB8200. I do like the idea I can run a dedicated line to a particular device(Apple 4K Gen2) and then run the secondary to my ASUS AX-88U for everything else. I just purchased the S33, but now I am contemplating on returning the S33 for the SB8200. I have Suddenlink 1Gig internet. Your thoughts??

    • I don’t think that applies to your situation, Derrek. You can only use two ports on the 82000 if you use Link Aggregation (which doesn’t seem like your case) and on the S33, only when you have two static IP addresses. In short, either will make no difference in terms of ports, but the S33 will make sure you get 1Gbps in full (when you use its 2.5Gbps port.) So keep it.


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