Xfinity only allows 35 Mbps upload, but my modem supports 800 Mbps up (plus 2.5 Gbps down). Why is Xfinity artificially capping my speeds?

As in the title. I have a modem, a Motorola MB8611, which can do 2.5 Gbps download and 800 Mbps upload. However, Xfinity says it only supports 35 Mbps, which is completely wrong, by a literal order of magnitude and then some - it literally supports over 20 times the speed Xfinity says it does, and 8 times the speeds I expect.

When I upgraded, the Broadband Facts and the representative both said I would get 100 Mbps upload (which is still just a fraction of what the modem can do), and I made sure when I bought this modem that it supported those speeds. That being the only reason to upgrade, I expected the full upload speed, but it seems Xfinity is artificially capping me because... they don't like my modem, or something? They want me to buy theirs and have decided to act in subterfuge toward that end? I don't get it. There are modems on that list with a fraction of the bandwidth of mine, and Xfinity allows those a 100 Mbps upload speed, yet mine is left in the gutter for some inexplicable reason.

I get that actual traffic, bandwidth, network behavior, etc. will change and depend on network conditions, but I expected and still expect that Xfinity at least tries to allow my hardware to do what it says it can do rather than artificially cap my speeds because they think I don't know any better. This is completely ridiculous, and completely dishonest on Xfinity's part.

Anyway, my neverending complaints with this godforsaken company aside, is there a fix? Thanks.

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BruceW

Gold Problem Solver

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27.7K Messages

2 hours ago

... Motorola MB8611 ... it literally supports over 20 times the speed Xfinity says it does ...

Manufacture's speed specs are almost always higher than the speeds Comcast/Xfinity lists.

The 8611 is not compatible with the "enhanced" upload speeds. Follow the "See all modems" link near the bottom of https://www.xfinity.com/support/internet/customerowned, and then check the devices listed under the "Compatible modems for enhanced speeds" heading. The 8611 is not on that list. In fact no Motorola models are. AFAIK Comcast/Xfinity has never said how they determine which devices are compatible with enhanced speeds. The charts on that page are pretty much all we know.

user_dw9rle

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3 Messages

This would make sense... if the supported modems for 100 Mbps didn't have a fraction of the bandwidth mine does to begin with. They're DOCSIS 3.1, just like mine, and the stuff I see posted elsewhere mentions mid-split is the requirement, and the MB8611's upstream supports a frequency range of 5 to 85 MHz, which covers that split range. There's no technical reason they could possibly have to not negotiate 100 Mbps upload, and their notes about supported modems still only say that the behavior may be different, not that those are the actual hard requirements to get the speeds.

Anyway, that site even says my modem is optimized for the plan I selected, showing that plan is 35 Mbps, which just tells me Xfinity put me on the wrong plan despite what the labels and agent both say. There's some configuration issue on their end, I know it's not a technical or hardware issue.

(edited)

1 hour ago

user_dw9rle

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3 Messages

Just another detail, I have other reasons to think I'm on a plan that isn't the "1 Gig" they promised - mainly that the plan listings show the plan they put me on (showing 35 Mbps), right next to a second plan I could choose to upgrade to also called "1 Gig", with different features supported (including 100 Mbps); and the Broadband Facts labels also have an option for my plan, which has no label at all, and then another tab in the list with a label, for "1 Gig", that shows the specs I expected. So, somewhere in their configuration for me, I know for a fact I have something that is registering as different than the plan I was told I was buying, and it seems that the plan I'm on is not even attempting to use the full upstream frequency my modem supports - because, I'm guessing, it's a legacy plan configuration they assigned me. Which, again, I get that the actual behavior and speeds may be different, but I at least expect that I am allowed the next-gen speeds, and that the connection to Xfinity uses the actual specification of my modem rather than being artificially capped because... who knows why.

(edited)

1 hour ago

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user_dw9rle

Xfinity only allows 35 Mbps upload, but my modem supports 800 Mbps up (plus 2.5 Gbps down). Why is Xfinity artificially capping my speeds?

BruceW

user_dw9rle

user_dw9rle

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