Comcast internet speed - fake or not?


I use a Netgear C3700 cable modem with a Comcast contract for 60 mbps. I use wifi for everything. When I run the comcast speedtest url I get 70 mbps. When I run 6 others including cnet, att, ookla, the max I get is 22 mbps with most between 9 and 16 mbps. I call comcast and they say the Comcast test is correct, but cannot explain why all the others are not even close. What am I missing? Fake or not Fake?


My ISP is Spectrum (Charter) and I just ran the Xfinity test and the Spectrum tests (Spectrum uses Ookla for the test). Spectrum shows 115Mbps and Xfinity shows 112Mbs for my connection.


Thanks Paul - What speed are you paying for?
Last night I reset my modem and Xfinity and Speakeasy both fell to 16 Mbps.
This mornings results - I added Spectrum
71 - Xfinity
70- Speakesy
25 - CNET
17 - Broadband Place
17 -
17 - ATT
17 - Ookla
16 - Spectrum
12 - Toast
12 - ZDNet
71 - Xfinity 2nd time
70- Speakesy 2nd time
All on wifi - Any comments - I pay for 60
Will try all direct next on ethernet


I’ve used for years to test connections. You just go to the site and hit the big GO button in the middle of the screen (I mention this because they have ads all over the screen that could be deceptive).

Keep in mind you want to be running tests from a wired connection, that is what your ISP would be guaranteeing. Once you add wifi to the mix you are introducing additional factors (distance to/from access point, interference from other wireless devices, objects the signal has to pass through) that will affect your connection speeds.


And thanks Larry. I ran all the above speed tests on ethernet and all but the last two, Toast and ZDnet, gave speeds between 60-70 Mbps. Toast and ZDnet had no change. So throwing out Toast and ZDnet for any future testing. Moved back to wifi and retested and got same original results as before.

So this being a Geek Forum - when on WiFi, how does testing with xfinity and spectrum speed tests produce 60+Mbps and the others produce only 16-20. Perhaps xfinity tunes its protocols to the Netgear C3700 and the others use generic protocols? Is there any “tuning” I can do to the modem?

Which begs the question. If xfinity can tune their speed test protocols for wifi, What is Windows 10 doing if using its protocols when relaying the speed tests of the other programs. Which might mean that because Windows 10 is doing the transfers and not an xfinity driver - then my normal speed without an xfinity driver is really just 16 Mbps. Is anyone aware of an xfinity wifi driver for Windows 10.


I doubt the Comcast speed test is fake; connections to different parts to the Internet will have wildly different speeds.

When I use to check my system, I often choose different servers to see what’s going on. Connecting to different networks can give me wildly different results.

I think the issue here is that Comcast just has lousy peers in your area. This isn’t a surprise, since Comcast is widely regarded as the worst of the major Internet service providers right now.


One more test tried. I have been using a Lenovo X1 Yoga (1st gen) and uninstalled the Intel WiFi driver and rebooted and checked that Windows did not re install it. So ran these with the Windows WiFi drivers I assume. And ran the tests again on WiFi and got the same results. Xfinity and Speakeasy speed tests show 70 Mbps and the others, (ATT, ookla, etc) around 16 Mbps and varying distant servers did not differ much.


It could be that different speed tests know you are on wifi and others don’t. So the higher speeds you are seeing are actually being done from the router and/or modem, while the lower speeds are testing from your device over wifi.


The cheapest option from Spectrum, 100Mbps down and 10 Mbps up.


Thanks for all the help. I have learned the most about network speeds from who also provides a lot of discussion on net-speeds - well worth reading beyond just their speed test.

The bottom line is that using the big ISP’s provided speedtest could strongly be a FAKE: "these servers are on an internal network server [like a private LAN] and they WILL NOT give you real world results. Using xfinity’s test on an ISP that is not theirs will probably give a real world test. Using it on their ISP may most likely NOT be real world.

So I am trusting two tests from now on. and by Ookla. Both seem to give comparable real world results on my Xfinity ISP of 17 Mbps.

While the Xfinity provided speedtest gives 72 Mbps. Just BS, aka FAKE.

Know what your real world speeds are when you search for an ISP comparing speed vs cost.


When the slowdown is outside of Comcast’s network they almost certainly have no control over the speed. By US law the speed guaranteed is only between the customer and the ISP because once the data flows outside of the ISP’s network there is usually no way for the ISP to control the speed of other companies Internet routing.

Based on my tests above Comcast clearly is providing good speed across their network border where my data crossed since I got good speed measurements going from LAN -> Spectrum -> Internet -> Comcast -> Internet -> Spectrum -> LAN.


Historically I haven’t had any issues getting the speed results I expect when using something like, so I would be contacting my ISP if I weren’t getting the speed that I am paying for. I know for a fact that the speedtest works for speeds well beyond 60Mbps, so I certainly wouldn’t accept getting 17Mbps on there if you are paying for 60Mbps.


Good points. I agree with Paul on his points that Comcast is giving me the 60Mbps down, just like being on a LAN - just them and me, but that is not real world. Believing what I am seeing would erroneously make me want to think that the internet is running at 17mbps as that is what all the other speed tests suggest and that Comcast is just giving me what they get. So because I am only buying their minimum 60 plan or perhaps they don’t have the network resources, they are throttling me back to 17mbps. So on the one hand NOT Fake just between the two of us, but on the other really big FAKE as not real world. I called once and got the foreigner voice that claimed I was getting what I am paying for. Do you think If I bought the 150 or 250 or even Gig plans, they would be interested in giving me more bandwidth. Just did a retest of different speed tests and nothing changed except for one test I had use the local Comcast server and got 70 mbps which is in line with Paul above. on any other server is 17 or less. Looks like folks who have non-Comcast ISP’s get real world throughput based on what you are paying for. Any suggestions on who at Comcast to call next.


You should be getting what you pay for. I pay for 25Mbps down, and that’s what I get through Xfinity.

One thing to keep in mind is not every server out there will be capable of giving you that speed. Your ISP should be allowing up to that bandwidth, the server sending you your download (or whatever) may only be capable of 17Mbps.