Customer Provided Modems Will Not Get Gig Speeds on Xfinity Plans

I got the Comcast Modem and it dont get gig speeds either. Always about 1/3 of a gig. Maybe because of high usage because of virus. I would sometimes get in the 900 range before this. 

Interested to see if you get higher speeds when this thing is over. My 2 year contract is running out and I am interested in getting my own modem again. Tired of their box and modem rental fees.

Same here. I activated three different Arris SB8200 that I purchased and was still getting less than 1/3 of the speeds. I decided to rent thier gig modem to see if it would improve which it did for one day (500mbps) and then it went back to around 150mbps. Gonna drop my plan down to the blast speed which it did better when I had it even during the pandemic. I believe comcast is throttling down customers with the gig plans during this pandemic to even out the bandwith until this is over. When I was on on the blast plan I was actually getting more than the speeds advertised during the pandemic. 

Arris T25 modem connected to Netgear R6400 router.  946.4 down, 40.5 up.

Just upgraded my plan to 1GB and had to buy the SB8200. I'm getting 750mbps download and 38 on the upload with it wired via an ethernet cable. I've seen no increase on my wifi speeds from making the change.

CM1000 >Netgear RAX200>iMac.  

Constant 930-940  down and  40 up

@spongebob2004 Are you connected over wifi or ethernet cable? Also how do you like that router?

spongebob - I have a CM1000V2 that I just bought and I'm getting 2/3 of my plan speed. Getting 200 mbps downstream. My OFDM SNR is 30-31. Would you mind sharing your basic/cable-connection pages with levels so I can see what your SNR and power levels are as comparison??  I suspect my downstream OFDM signal/noise ratio is too low.  Here are mine:

I pay for gigabit speeds and get 95mbps at best. Comcast doesn't deliver a desirable service and could care less about its customers. Especially in areas where competition is non-existent.

I have a Arris T25.  I get great speed (down>930 Mbps, up>37 Mbps) but periodic outage, see https://forums.xfinity.com/t5/Your-Home-Network/SIP-DNS-Query-Failure-Periodic-loss-of-Internet-Manual-cycle/td-p/3354139

Screenshot

[Edited original response stating top speeds of ~600]

Well, I have no idea what changed, or what happened out in the universe, but wired speeds are now showing 890-920mbps (on the Xfinity speed test site)

My previous tests were on Xfinity's site (the 500-600 speeds) but they are solid now. Other speed tests sites still show anywhere from 450-650, but I know that Xfinity won't back results from those sites, so that's not a battle I am going to fight.

I guess I can just be happy now that Xfinity's site is showing the correct speeds. Now I can sleep 🙂

Since I've always had daily issues with Comcast, I decided just to spend as much money as I could so surely I'd stop having daily issues, right?  I was informed that the cost of fiber-optic installation was about $500 for my area, etc - No matter, I decided whatever it takes;  I've had this service for about a year now (estimate).  So I sit here with my laptop wired to a Netgear CM1000 trying to get my internet going again and just ran a speed test:  246.0 Mbps download, 40.7 Mbps upload, Latency = 18ms (whatever that means)...  I'd say this is lackluster, especially since my internet service cuts out 13-18 times per week, and my TV loses signal and/or the image gets all blocky with no sound or distorted high-frequency sound.  Awesome!!  I think I'll purchase the CM1200 next...  Interestingly for the service calls, nothing has been wrong inside my home - the technician told me the signal was way to high outside, and gave the analogy of someone screaming into my ear vs talking at a correct level so I could understand... And Comcast charged me a fee for inside my home even though nothing was done there >> any they refused to reimburse the charge.  Yes, directly stealing from me.  I pay well each month.  Sometimes I'm very upset and do not want to pay, but... I suppose I'm a prisoner.  Thank you Comcast.  You are terrible.