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szmad
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Tuesday, January 13th, 2026 3:47 AM

Xfinity says my modem is too slow for my maximum service speed -- are they right?

I have an Arris surfboard SVG2482ac, from about 2020. I use it with Xfinity/Comcast Cable. I recently upgraded my Xfinity from 500 Mbps to 1000 Mbps. After doing this, Xfinity sent me an e-mail saying that they checked my modem and determined that it cannot support the maximum new speed of 1000 Mbps. I checked the technical specs for the Arris surfboard SVG2482ac and I found conflicting information -- some places say that it can support 1000 Mbps, others say 800+ Mbps. So what is the deal here -- is Xfinity right, and I need to upgrade my modem if I want to get the full 1000 Mbps service, or are they wrong?

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BruceW

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2 months ago

... Arris surfboard SVG2482ac ... upgraded my Xfinity from 500 Mbps to 1000 Mbps ...

Manufacture's speed specs are almost always higher than the speeds Comcast/Xfinity lists. The SVG2482AC is not compatible with Gigabit internet service. Comcast/Xfinity rates it for wired download speeds "up to 857 Mbps". It isn't compatible with their "enhanced" upload speeds either.

Follow the "See all modems" link near the bottom of https://www.xfinity.com/support/internet/customerowned, and then under the "Compatible Modems" or "All compatible modems by brand" headings click the Arris list.

Using devices on Internet speed tiers for which they are not compatible with tends to produce unexpected results, often speeds well below the ones you are paying for. AFAIK Comcast/Xfinity has never said how they provision devices operating on speed tiers they're not compatible with. All I can tell you is that many customers who tried it have reported that they don't get full speed. There's a tendency to think the device will operate at the maximum speed it is capable of, but that doesn't seem to be the case. Instead, incompatible devices often seem to be provisioned to run at speeds well below what they should be capable of. 

Suggest you either get a device compatible Gigabit, or drop back to a plan speed for which the SVG2482AC is compatible. 

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

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EG

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2 months ago

The concern is not "Community Center / Guidelines" help related............ Topic moved here to the proper help section. 

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szmad

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2 months ago

Thanks Bruce. I need two voice ports, and don't need wi-fi, so there is only one compatible product -- the Netgear CM2050V. 

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XfinityShawn

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szmad Will you be making the change to a new modem to get those upgraded speeds? Once you do, my team will be here if you should have any issues. 

 

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2 months ago

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zandor60657

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@szmad​ I have a Netgear CM2050V.  We got run through the ringer waiting to get next gen upload speeds.  It was briefly approved for a couple months, then pulled off the approved list and we all got our firmware downgraded because some people were having stability problems.  Then we waited a year or so and finally got the CM2050V back to approved and fully working.  At any rate it's all good now, at least as far as I can tell.  I have 2100/300 service and it seems to be working properly.  Actually hitting the 2100 down is rare but occasionally happens.  Ookla speed test will usually hit it.  I've gotten a couple video game downloads from Steam to hit 2Gbps too.

Your old SVG2482AC won't work for higher speed tiers.  It's a DOCSIS 3.0 modem.  Higher plans require DOCSIS 3.1, so you need a new modem.

DOCSIS 3.0 modems can support up to about 1Gbps, but not on Comcast's network.  It used to work, but not anymore.  They're phasing out the 3.0 channels and replacing them with 3.1 channels. I used to have 32 downstream 3.0 channels, but now it's down to 24 and I expect it will keep going down.  They're moving the bandwidth to the 3.1 channels.

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1 month ago

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