ARRIS Surfboard S33 DOCSIS 3.1 Multi-Gigabit Cable Modem | Approved for Comcast Xfinity, Cox, Spectrum & More | 1 & 2.5 Gbps Ports | 2.5 Gbps Max Internet Speeds | 4 OFDM Channels

This is my second time buying the ARRIS S33 DOCSIS 3.1 multi-gigabit cable modem—because lightning apparently decided my internet setup was too good and struck down my first one like Zeus himself was having a bad day. RIP, my beloved modem, you lasted just long enough to show me what true speed feels like before being vaporized in a flash. But honestly? I’m not mad. The ARRIS S33 is a beast. It supports DOCSIS 3.1, meaning it’s ready for the next-generation high-speed cable internet—like, up to 2 Gbps downstream and 1 Gbps upstream (if your ISP and plan are playing along). It’s also backwards compatible with DOCSIS 3.0, so if your ISP hasn’t fully upgraded yet, no worries. Installation is impressively painless. Plug and play, with support for IPv4 and IPv6, and it handles channel bonding like a champ—aggregating multiple channels to maximize throughput and minimize lag. I’ve thrown all kinds of traffic at it: 4K Netflix, intense online gaming sessions, video calls where my face looks mostly presentable, and it doesn’t even break a sweat. The only caveat: lightning doesn’t play nice with electronics. So if you live somewhere prone to storms like me, consider a surge protector or UPS, unless you want to keep buying backup modems like this is a weird hobby. Bottom line: the ARRIS S33 is fast, reliable, and future-proof enough to handle whatever Comcast Xfinity throws at it. Just pray to the weather gods to keep your modem alive.

I should start out by stating that I am an IT professional, and have been in the industry for 24 years. I have a family of 6, all of whom are doing school remotely in this COVID world, and I've worked from home for the better part of the last 8 years, so home Internet is my livelihood. I also have one gamer in the family who tests bandwidth and connectivity to its limits for me. We moved (in town) November of 2020, so I have been on a Netgear C7100V for the past 5 months. Which, granted was its own Wifi router (2-in-1) and had a smaller price point, AND was an older model than the Arris S33. For the last 45 or so days, while on the old Netgear, my Xfinity connection had been dropping periodically. Turns out the Netgear C7100V was recently removed from the compatibility list. I figured I better buy a new modem that was on the list before I call Comcast and complain because the first thing they're going to say to me is go buy another modem before they'll support my problem. Buddy of mine in IT had the Arris S33 Surfboard, and raved about it, so I thought I'd give it a try. And because my old Netgear was a modem/router combo, I had to purchase routers too, so for context, I should disclose that I also upgraded to an Eero 6 pro 3-pack tri-band mesh wifi6 router system too. BUT, I can say unequivocally, that I never got anywhere close to the 1Gbps speeds I was paying for with the Netgear C7100V. 600mbps, tops, which is a bandwidth limitation of that device that I lived with and dealt with because no one ever got 600mbps TO the modem over wifi anyway, so the bottleneck was before the Internet egress before anyway, and still is, and probably always will be with wifi, but I digress. But with this Arris S33 Surfboard modem, I get a consistent, all day, everyday, 900+mbps of my 1gbps service. And, so far, no drops in service either since installing the Arris (fingers crossed it's only been 3 days). But even if I do, this review is still relevant because if I continue to experience drops even after the new modem and router, pretty sure it's the service provider at that point anyway. It's smaller, easy to use, quick simple setup, and if you have the Xfinity app on your phone there's no need to even call Comcast. You don't need to be an IT pro either. It took, like 20 minutes to setup, using the included quick setup guide, and it's been "set it and forget it" ever since (again, so far). I'll come back and revise this review if that changes, but I have no complaints.

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.

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.

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.