Comcast Bandwidth Deception

This post is more than 3 years old.

I work on the Internet. Having a fast Internet connection is an important part of my work environment. At home, I also use my Internet connection for entertainment and home automation. When my Internet connection is slow or isn't working, I notice.

For the last few months I've been a reluctant Comcast cable Internet customer, after technical and speed challenges with the local DSL provider I was using couldn't be resolved. I pay for a 25Mbps download speed service level with Comcast. But almost as soon as we had service turned on, I started noticing that from around 5 PM until around 10PM or later, our available speeds would significantly decrease - sometimes down to 1Mbps or lower.

I contacted Comcast about it. After all the usual ridiculousness where they try to sell me phone service, tell me I need a new cable modem, tell me it must be squirrels, etc, we got to the heart of the matter:

Me: Is our bandwidth shared with other users, or should it be protected even during peak times?
Comcast: It's not shared at all.

I didn't believe them, but I believed that they wouldn't admit to the bandwidth being shared. So I started collecting data to prove otherwise.

Using a command line tool to query the service, I set up a script that would run once every hour and record the currently available download and upload speeds, as well as ping time. I put all that in a spreadsheet. After two months, I graphed the average upload and download speed available at each hour of the day:


Clearly the available download speed drops off significantly starting after 4 PM (Eastern time), and increases again after 10 PM. This coincides perfectly with known peak times of home broadband Internet usage, as people come home and start streaming music, movies, TV shows and other data.

So I contacted Comcast again.

Me: Can you confirm that when other customer usage increases during the evening, our speeds are slower because we're sharing the available bandwidth?
Comcast: There a lot more customers using internet service during the evening. So, we can expect more connection traffic.
Me: Is it your understanding that we should be able to get the 25Mbps speeds even during peak times?
Comcast: Yes, even on the peak times, you should get the correct speed you signed up for.

They scheduled a technician to come out to "check my equipment." At first I had trouble getting them to schedule one to come during peak usage hours, so they could actually witness the issue, but they finally set an appointment for 5-7 PM.

Right before the appointment time, the technician called. When I re-explained the issue to him, he said "Yeah, we've been getting a lot of reports like that here. Basically it's a capacity issue where there are too many people using the same bandwidth. There's a node in town that needs to be upgraded, but Comcast won't do that."

When I asked him how I could prompt that process along, he said there were no known phone numbers to call or addresses to write to that would help with this. He said the only option was to keep contacting Comcast about it and that hopefully enough people would raise the issue over time so that Comcast would finally relent and expand capacity.

I don't normally blog about this kind of "first world problem." I have my health, my life is fine, this isn't a big deal in the scheme of things. But I find it pretty galling that Comcast would so blatantly deceive its customers about a known capacity issue, one it could address with relative ease - and one its own representatives say it should address.

So, there's the evidence. I have the full chat transcripts and spreadsheet data if anyone needs them.

Comcast, it's your turn to do the right thing. I won't hold my breath.

9 thoughts on “Comcast Bandwidth Deception

    1. 8 years later Xfinity is still up to their old deceptive practices by calling their newest product "10G", even though it gets nowhere near 10GB speeds. Nor is it the successor to our on any way related to the wireless 5G network. But your average how or Jane doesn't realize that. This is deception. Plain and simple. In some locations up to 4 or 6gb max is possible, but in most places xfinity "10G" tops out at around 1gb. That's assuming you actually get the bandwidth advertised, but as you've astutely observed, the stated speeds are not usually achieved.

      Xfinity's deceptive & confusing marketing practices are annoying as hell and I will never go back, even if it means accepting a lower speed or paying more. Fortunately, I have to do neither since they installed Google fiber on my street last year.

      While Google may no longer espouse the "don't be evil" mantra, the consistency and transparency of their service has been a breath of fresh air. No new customer discounts that punish loyalty; no long term contracts; and the equipment is included in the price of service. This last part actually makes Google fiber cheaper then Xfinity for me as the price for service is the same, but the Xfinity modem rental adds another $15 / month.

      Google fiber even asks you a few questions about your household Internet usage so as not to sell you their 2g product when you don't need it. I'm a software engineer who works from home and I can't even take full advantage of the 1gb service (yet), as wifi speeds don't reach 1gb yet. My next project is to run cat6 cable through the house so I can actually make use of gb internet.

      So to make a long story longer, like you, I despise xfinity's deceptive practices and I'm through with them even if that means higher cost of slower speeds. Fortunately in my case it doesn't.

  1. Anyone complaining about Comcast should spend some time dealing with AT&T, which has the worst customer service of any company on the planet.

  2. I want to know if Comcast's Internet speed website ( can be trusted. I am supposed have a 75 Mbps Internet connection. The differences in upload and download speed results between Comcast's test site and Speakeasy's speed test are startling. For example, with an Ethernet cable attached directly to Comcast's gateway device, the results on Speakeasy were an average of 30.78 Mbps. I ran the test three times, waiting at least five minutes between tests.

    Conducting the test on Comcast's site recorded an average download speed of 89.65 Mbps.

    The server location for each test was in my local city.

    It is readily apparent that browser pages are not loading in accordance with an 89 Mbps Internet speed.

    1. yep, they baited me into the 75mb download/HBO deal. It cancelled my previous contract and after 1week when there service was not what was sold to me they refused at management level to let me return to my previous contract every though they had said I had 14 days to try/return it. They negated saying this would then leave the original contract void and we would have to start all over. I had been sold the original $30/30mb deal for 2yr and they were probably looking for way out because they lost money on it.
      I opted after saying no three times to the 'salesconman at Comcast because I was able to return it - that act is for pathetic companies, I would have thought better Comcast. And yes I am now paying double for internet although now at 75mb download speed. This would be acceptable if it was not throttled at 29.9, I can get 38mb at 3am but otherwise it is between 9mb and 30mb what a joke.

  3. Thank you for doing the work of documenting. I specifically got a high-range modem/router to prevent problems with staying on the internet in the room I occupy furthest away from the modem. It did not help. I have been doing speed tests and have had a wide range of results, with most way below what I am supposed to get for a "Performance" plan like yours. They say in the service plan agreement that the internet speed connection may vary, but it seems to me that there should be a guarantee to perform within a certain range of speeds close to the average and for a high percentage of the time. It makes me mad that they can get away with not having to be accountable for at least a certain level of performance.

  4. It doesn't appear that you've added anything to this since then, so I would like to ask: have you gotten Comcast to upgrade the node in your area?

    If not, I have a recommendation - there are a few different things you can do.

    1.) Call Comcast Executive Customer Support (google it, freely and widely available). If you don't get anywhere with that, go to number 2.
    2.) Attempt to email the CEO of the company. Some digging around should find the email address format for the company (first initial last name [at], etc.). Email all of the executives for the company with your data. Be very kind. You get more flies with honey than you do vinegar.
    3.) If you're unsuccessful in finding their email addresses, deliver a certified letter to his home. Use property tax records to find it.

    If you need any help, feel free to email me.

    1. It took quite some time and plenty of phone calls to Comcast before finally getting my Internet speed issue resolved. First, do a Wi-Fi network scan and find out how many Wi-Fi signals are within range of your home or Wi-Fi location. If you have a significant number, invest in a decent dual band router that has a 5 GHz capability. Test your Internet speed and compare it with the speed values of the 2.4 GHz side of the router. Attempt to improve the results by experimenting with various channels within the 5 GHz range.

      Be certain to install the router in a location that is most favorable to achieving the maximum Wi-Fi signal strength and speed.

      If you have done everything possible to obtain the Internet speed as specified within your Comcast agreement, remember that Comcast can come up with a million and one excuses for why the speed isn't as advertised. Be persistent and vigilant until you either get what you are paying for or just compensation to make up for what you are being shorted.

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