ARRIS SURFboard S33 DOCSIS 3.1 Multi‑Gig Cable Modem | 2.5Gbps + 1Gbps Ethernet Ports | Works with Xfinity, Cox, Spectrum | For Cable Internet Plans up to 2.5Gbps | Modem Only, Router Required

I've used this modem for just under three months now. It's been fairly solid. I don't have any real complaints that would make me not recommend it. For a couple days I was only getting around 150 Mbps and couldn't figure it out for the life of me. Eventually plugged directly into the modem and did a speed test and finally got the speeds I was expecting. Turns out I didn't update my quality of service settings on my router. The router was acting as a bottleneck. Once I ran another speed test with the router and updated the QoS, I got the full bandwidth I was expecting. Pros: It's fast and as seamless as any other Arris or Motorola. I have 1 Gbps service and it's gotten very close with the various speed tests. I'm assuming that's a combination of advertised vs. actual speeds from my ISP and I don't suspect it's the modem. This should last me until the modem itself fails. Even streaming several devices simultaneously at 4K wouldn't crack 1 Gbps. Heck, even if we get 8K in the future, this thing could take several devices at once. The one benefit I see to having >1 Gbps is for file transfers if you work from home and work with massive files. Even downloading 50-100 GB files via cloud servers hasn't come close to Gbit speeds. Cons: For some reason, internal pings to the modem are now being blocked. Maybe they were always blocked but I could have sworn they weren't. That's a new one for me. This is an incredibly minor downside, but as advertised, only one ethernet port is 2.5 Gbps. Fine. I don't see how anyone in normal use cases would need more than that. This is the modem, not a router or switch. I do wish there was a way to send a reboot signal from within the network, but there are probably security or other issues with that. I think the first router I owned had that. Would be kind of useful, but barely worth mentioning. Other: It claims it has an app. I have almost zero idea why it would need one. Overall: Hopefully this is the last modem I buy. Seems likely. Would recommend. Edit: Cleaned up units.

I rented a Comcast router for years (how was I such a sucker!?) but when we recently upgraded our service to 1 GB speeds, I decided it was time to upgrade all of our hardware and stop paying $15 per month to rent their modem when I could buy one on my own! I did some research and this seemed to be the best option to take advantage of our new higher speeds. This modem combined with the Eero Pro 6 mesh routers system has lightning fast internet speeds reaching every corner of our 3,400 sq ft. house. I took this modem in the box to a local Xfinity store where they provisioned it to work with their service (they just needed the serial number and IP address) then took it home, plugged it in and used the Xfinity app to get it set up. It literally worked perfectly right out of the box and was super easy to get up and running. Just plug and play! My speed tests on my phone are coming back at around 950 MB/sec which is everything I could hope for! We've now been using this modem for about a month and have had ZERO hiccups or drops in service/connection. Internet is blazing fast and reliable, modem plays nicely with router setup. I truly couldn't ask for anything better, and now I'm not having to pay to rent Comcast's equipment! Yes it was a little pricey, but it will pay for itself within the first year, and I like having my own equipment now. I have nothing but good things to say about this modem so far. If we have any problems with it in the future I will absolutely update this review, but so far it's been an absolute dream. Anyone who says it doesn't work with Xfinity service or had a ahrd time setting it up either doesn't know what they're doing, didn't follow the directions properly or the problem is coming from Xfinity's end, because the modem worked perfectly exactly as it should right out of the box when you follow the directions and make sure to have your provider provision it for use PRIOR to plugging it in for the first time. I sincerely hope this review has been helpful to someone else! And yes, I paid FULL PRICE for it! Feel free to ask any questions.

The ARRIS S33 modem was a great upgrade. My prior modem was another ARRIS product and it worked really well. I've had several ARRIS products and all have functioned without issue. The only reason I upgraded was because my old modem was running DOCSIS 3.0 and I wanted to move to DOCSIS 3.1 to get the most out of the 1.2Gps service that I'm paying for. This new S33 modem improved my speeds across all devices by well over 100Mbps. On my M1 iMac I'm now getting 950 Mbps on average. The ARRIS S33 modem is a five star product. I'll summarize the rest of the story so you don't have to read it if you don't want to. You CAN use this modem with your Xfinity service. But you're going to have to work to get it done. The saga below is provided so if you decide to activate this with Xfinity, you'll have an idea of what you'll go through. Now for the ugly: installing this modem with Xfinity service... This is a simple modem. It's designed to be pretty much plug-n-play. Connect coax, plug in power, plug in ethernet cable then activate through Xfinity's app. All the connections on the modem are simple. I went to Xfinity's app to activate and the activation function wouldn't work. It said I had to contact an Xfinity agent directly. So I started the chat with an Xfinity agent. I spent over an hour chatting with the agent as they tried to figure it out. First they said the modem isn't compatible with Xfinity's service. I pointed out it's the recommended modem on Xfinity's website. Then they said they couldn't find the modem in their system so couldn't register it on my account. More haggling. They escalated the issue. Escalation agent had the same problems. After more than an hour they told me I'd have to take the modem to a service center because "the service centers have special tools to scan the modem into the system directly." He assured me no appointment was necessary with my case number. Off to the Xfinity service center I go. I get there and it's a 45 minute wait. The guy says their case number doesn't mean anything to them and I'd still have to wait in line. The guy calls my name and I walk up to the counter. As soon as I lay the modem box on the counter the guy says, "Oh, no. Another one of these." He proceeds to tell me he'll do everything he can to help but they've not been able to do anything with these modems in the service center. He says the service centers don't have any special tools and have to do the same things the online agents do. And he comments that he wishes the online agents wouldn't tell customers what the service centers can do, they're always wrong and just dump problems on the service center. Sure enough, the modem isn't listed in his system either. Nice guy and admits this situation has been causing a terrible customer experience with several customers. He escalates the case to some tech group offsite. He gives me a new case number and says they will have to try to manually configure the modem for my account and I should get a call within an hour. I walked out ticked off and skeptical that I'd get a call or that they'd fix it. 50 minutes later I get a call. A nice guy from the Xfinity tech group tells me he's got it configured and it should install fine. Just have to activate it through the app. I reinstall the modem and go to the Xfinity app to activate. Same error in the app as before and it makes me contact an agent. So I start the chat and explain the situation. The chat agent says to give him a few minutes to review and attempt the activation. He comes back on about 5 minutes later and says it's activated. Sure enough. The modem light is blue and I once again have data flowing. It took somewhere about 4 hours, two chat sessions, a trip to the local service center and referral to some higher Xfinity tech group; but it finally got installed.

10-22-25 Update. So far the modem is working fine. I have not noticed any issues. I did some speed tests are it is about the same as the day I installed it. So far so good. ** Sorry about the 1 star rating but that was because the shipping was so slow and received an open box after all that waiting. 5-17-24 Update. I wanted to try to get a replacement unit hoping it was new but Amazon system would not allow me to replace it with same unit but another merchandise only. So, I asked for refund into my CC and tried to buy another new one. A used unit popped up so I ended up buying it for about $100 less than new (which was in my opinion same as what I originally received.) Used unit (described as acceptable condition) arrived fast and it was in great condition, no visible scratches nor damage. I had to spend about 25mins on the phone with Cox Tech (took longer than it should have because numbers and alphabets are hard to get it right) and it was activated. After that, it was just a matter of turning off the router and restarting it. So overall installation was relatively painless. The download speed almost doubled and upload speed tripled compared to old modem so happy with this unit for now. I am equally concerned about longevity. I am not sure how long this will last but my last Arris Surfboard which this replaced did not break but was due to outdated speed. I will update this review as needed. Original Review - 5-12-24 I bought a S33 on April 9th with expected delivery in 10 days which was long but ok. There were two delays in shipping and finally received it on May 12th. When I opened the outer shipping bag, the box was open (tape seal was already cut) and all the plastic bag was cut open. Clearly not new and who knows what condition?????. I could have bought a refurb unit for $60 less and I received a questionable "New" item. I had not tested the unit since I was upset and returned it ASAP. I had kept dubious items in the past and at the end decided to send back but it was a day over so I had to eat it. so I immediately returned this item.

This product is excellent. It allows me to get the free extra bandwidth that Xfinity gives us when they over provision on gigabit speeds. My old modem capped me out at 960 Mbps even though they were giving us 1,200 Mbps of speed. With this new modem I now hit download speeds of 1,400 Mbps on my equipment that is capable of it. The reason I'm writing this review though is because I just recently had my modem quit working after about 14 months for no reason. The light on the front would stay solid orange with an intermittent flash of white about every 15 seconds but wouldn't go solid blue like it's supposed to do. It also had a very high pitched sound coming from inside it while it was trying to boot up. Had to call Xfinity out because they have been doing maintenance in my area so I/we thought they caused the problem. The technician spent 2 hours trouble shooting at my house and finally figured out that the ac/dc power adapter had gone bad. He read on the forums about it and it described my exact situation with what we were seeing and hearing. He did this by stealing the power adapter from my Asus router that just so happened to fit. He plugged it into the modem and it was up and on-line in about 2 minutes with a solid blue light. After the technician figured it out I contacted ARRIS who took me through some questions which described exactly what I listed above and they are sending me a new power adapter. That being said if yours is out of warranty here is the one you want to order on your own: https://www.amazon.com/gp/product/B09QM8S6R7/ref=ox_sc_saved_title_1?smid=AXZD0AJNQX5UZ&psc=1

Remember this modem is a modem ONLY and does not have wireless, so Its assumed you will plug it into your own Router that has WiFi. Its also provisioned for specific ISPs, so make sure its compatible with yours before you buy it. This is a well-matched modem that has two ports - one rated at 2.5gbs and the other for 1.0 gbs (in case you get two IP addresses from your ISP and want to run two separate networks at home). I found the "self-install" to be a disappointing feature (didn't work at all), but a simple call to your ISP to swap or establish the MAC address will have you up and running in one phone call. The only other thing I found disappointing was that me (and many others who have this model) cannot access the modem via our router... something I was able to do with my 300mbs Arris modem this one replaced. This modem has the same IP address as my old one did (many cable modems use 192.168.100.1), so it was a bit puzzling as to why I couldn't indirectly access it. If you plug directly into the modem AND power off/power on, you will be able to access the modem. So once you get "inside" the S33 about the only thing you can do is turn the light on the modem off or on (and change the password), so that turned out to be a bit anti-climatic for me. And the password, which is supposed to be "password" turned out to be the last 8 digits of the serial number (something I ended up finding via Google), despite the instructions in the box saying it was "password". But... this is a solid modem and I had my ISP come out to run speed tests to my junction box, inside my house and then on the cable coming FROM the modem (to my router). Since I am paying for 1gb service, I saw the equipment read at 1.2gb, so this modem is the real deal if you're jumping into 1gb or higher service. Arris is the company that took over Motorola, but they still carry the "Surfboard" name on their modems. A little pricey but you won't pay your ISP another dime in modem rental fees if you buy this baby. Stick it behind a UPS and it should last you just about a lifetime.

EDIT 3: Upgraded to Xfinity Gigabit tier. Getting around 935 down and 40 up. This is because I don't have a 2.5Gbps. If you have 2.5Gbps network setup, you should be getting 1.2Gbps (20% over provision from Xfinity end). Haven't had any modem issue since I got the product. EDIT 2: Running for more than a week now without a single drop. So, as far as the stability goes, I don't expect ever needing to restart. But of course time will tell. EDIT 1: Bumping to 5 star. Still pissed of lack of an ethernet cable on such an expensive modern. But it's running solid for 2 days and I ran a whole bunch of ping tests for my 2 favorites (this one and Motorola MB8611, both with 2.5gbps ethernet for future proofing) and after thousands of pings, I plotted in box plot and found that median and third quartile are both faster on this one by almost a ms. Not a giant differentiator. But even the single clutter free blue light won me over in the look department along with its super tiny form factor. Overall, I decided to return all the other 3 and settle with this in my quest for modem upgrade. Original 4 Star review (took out 1 star merely because of me being upset over not finding a network cable on such an expensive modem): I have been experimenting for last month or so with different DOCIS 3.1 modems. I bought Arris 8200, Motorola MB 8600 (Motorola is really made by Zoom telephonics) and 8611. Here is my initial impression: 1. No network cable in the box: I was really disappointed. The Arris 8200 had a nice flat network cable in the box. Motorola 8600 and 8611 had old style rounded network cable. And this has none! 2. It looks lot nicer than Arris 8200. The 8200 is so hideous that for the look alone I decided to return that. The motorola still probably wins the look (it's your personal choice). But given how big Motorola modems are, I would rather have this cute little modem. Speaking of which, the modem is really tiny (roughly same size as 8200 and actually a tad bit shorter and thinner). 3. Unlike 8200, 8600 and 8611, S33 actually forced me to call Xfinity to activate (the other modems activated without hassle via the xfinity app). Few observation about firmware compared to Motorola MB 8611 and Arris 8200: 1. Unlike Arris 8200, there is no spectrum analyzer on S33! At least I cannot access 192.168.100.1:8080 2. For me on S33 the SNR/MER is more or less same on all channels as MB 8611, except the OFDM PLC is showing 1 dB less than 8611 (may be it will get better as the modem locks in better). 3. The Power shifted by full -5 dBmV. While most of my channels on MB 8611 had 8 dBmV (except OFDM PLC which had -2 dBmV), the S33 is showing around 3 dBmV for all but OFDM PLC and on OFDM PLC it's showing -5 dBmV. So, the entire signal level shifted by -5 (and OFDM shifted by -3). 4. Upstream power level seems to be more or less same on both S33 and 8611. I just installed the modem. So, will have to test few days and observe Corrected and Uncorrectables before I report on those. On 8611 I used to accumulate low single digit corrected and Uncorrectable was very rare (less than 1 a day).

I installed this modem almost 2 weeks ago to replace my old Arris modem and it’s been great so far. The old one lasted me 8 years without problems, so decided to stick with Arris. The Black Friday deal was also pretty good. Plus, this one has 2 network ports on the back (2.5gb and 1gb) and I may use the 1gb port for telephony. Connecting the modem to Xfinity was super easy. I downloaded the Xfinity app, found where to add a modem, entered the modem’s MAC address, connected and powered on the modem - and was connected in a few minutes. This modem does not have wifi - which was perfect for me as I wanted to run my own wifi mesh network to cure my wifi dead spot problem. If you want to connect this to your own wifi router, it was recommended to me to get a Cat 8 network cable and connect it the the 2.5gb port in the modem and the other end to the router. That’s how I have it connected and I’m getting blazing fast speeds now. The Arris app didn’t really do much other than allow me to register my modem and view the manual. The main wifi mesh router is connected to the S33 and I’m getting consistent and incredible speeds everywhere in the house now - no dead spots. The wifi mesh system pairs really nicely with the S33 modem at the core.