Question

Bought SBG8300 for Comcast 1.2Gigabit Plan, Slower Speeds than before

  • 6 January 2024
  • 11 replies
  • 216 views
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Man,

From everything Im reading on this forum and Xfinity forums, I really should have thought sixteen times over about getting this model.

So:Looking for some suggestions here. I am a gamer, Xbox One Series X, PS5, Switch, you name it. I was not getting the speed I wanted to stream and game with friends, etc. I was paying Xfinity for one of their basic router modem combos and had the 800mbps plan. Surprisingly it was really decent speeds for that plan but my upload was capped and it was causing lag in certain situations. I bought the new router (SBG8300 which was listed as a compatible device) but Im not getting anywhere near the 1.2gbs and now Im hearing it doesn’t truly support the gigabit plans from individuals on here. Im thinking of returning this router tomorrow and getting a better model. Any suggestions on models?

 

I am getting like 250-300mbps on direct ethernet (expensive double braided ethernet), and seems like better speeds over 5ghz wifi. But I was getting 750mbps on my old plan and device. I really want to find the correct modem router combo (preferably in one) that will get me closer to the true “up to 1.2gigabit plan”. Any help or advice would be greatly appreciated. Ive spent a lot of money and christmas gift cards to get this device and Xfinity plan and it not only didn't improve my speeds, they got worse!

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11 replies

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Check Xfinity for recommended routers vs Max speed… there is a pdf file you can download.

you may have to login to Xfinity… they put the entire approved list at the bottom of the page.

 

Shows the model modem/wifi router and Max Speed (theoretical)

 

https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2023.11.22%20Full%20List%20of%20Compatible%20Devices.pdf

 

hope this helps!

 

Charles

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Having the EXACT same problem. I have been paying Xfinity for 2 years now for 1.2gigabit with this same modem sbg8300. The max download I have ever got with this modem on my 1.2gb plan is 800 almost 900mbps. But with different modems when I was paying for 600mbps I could get almost 800mbps. When I was paying for 400 I could get 600mbps.

Xfinity came out  2 weeks ago told me there was a problem with the line from the pole to my  house. He stated it was affecting other customers in the area. They rewired the whole house all new wire, the pole to junction box on side of house about 40ft around house to get inside and into SBG300 into modem. From sbg300 modem another 10feet wired cat6 directly into the PC. Right after install speeds dropped and max I get now is about 350. I use xfinity speed test or speakeasy speed test for testing.

According to the xfintiy installer the SBG3800 modem is not on his approved list.

I also installed a new 2.5gigabit PCIe network card into my PC and I got no change in speed.

In central IL,  Xfinity has a monopoly on the internet. I’m paying near $150 monthly for gigabit speeds (that is with the internet affordability discount) and cant even get 400mbps.

What am I missing, to have such a serious drop in speed on a Ethernet connected device?

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see the link I posted above.. 

 

the Arris S33 or G36 model routers… they might get you closer to 2.3Gbps (theoretical).

No I am not an Xfinity employee…. but a frustrated Xfinity subscriber just like you.  :-)

 

Hope it helps!

 

Charles

https://assets.xfinity.com/assets/dotcom/projects/cix-4997_compatible-devices/2023.11.22%20Full%20List%20of%20Compatible%20Devices.pdf

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Update, to my earlier post. Try this and then do a speed test again.

Hate to put you though this again but call the xfinity number and have them do a electronic reset of your modem. I would love to know your results.

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Since you are experiencing with slow speed on ethernet cable, I suggest you to check the cable signals to make sure all the signals are in range.

To check the cable signals, find the link given below:

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Cable-Signal-Levels

SURFboard Community Moderator Team
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I might just try the S33 or the G36 just for kicks and return it. Because I just paid $318 2 years ago for this SBG8300 modem. I dont think it was worth it.

I forgot say when I did steps above in my earlier post.

call the xfinity number and have them do a electronic reset of your modem.

 

I  now get speed test results of about 960 both on the xfinity speed test site and speedtest.net.

Which is weird because I kid you not, I have personally powered off my modem and hit reset on back of it personally many times in last 2 years with no change.

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Xfinity supports only an 800 Mbps plan for SBG8300. We suggest you revise you’re speed plan from 1.2 Gigabit to 800 Mbps and check the hard-wired speed by directly connecting the modem to the device. If still facing the slow speed check the ethernet cable and co-axial are proper without any damage and check the cable signals to receive an acceptable range of downstream and upstream levels. 

Please follow the below link for the cable signals

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Cable-Signal-Levels

SURFboard Community Moderator Team
B

I’m having a very similar issue. I used this modem/router combo at my last apartment and was consistently getting 800Mbps+ with a 1000Mbps plan from xfinity. I moved apartments literally two blocks down the road and upgraded my plan to 1200Mbps and my router/modem is only churning out 200-400Mbps. I have had two separate Xfinity techs come out to help with a professional install. The last one showed me hardwired to his handheld modem I can get over 1k Gbps, but when I use wifi or a hardline to my modem i’m consistently getting those lower values. 

 

For whatever reason my modem/router decided to just give out during the move. I’m only a year in to my warranty and am considering getting a replacement..

S
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I’m having a very similar issue. I used this modem/router combo at my last apartment and was consistently getting 800Mbps+ with a 1000Mbps plan from xfinity. I moved apartments literally two blocks down the road and upgraded my plan to 1200Mbps and my router/modem is only churning out 200-400Mbps. I have had two separate Xfinity techs come out to help with a professional install. The last one showed me hardwired to his handheld modem I can get over 1k Gbps, but when I use wifi or a hardline to my modem i’m consistently getting those lower values. 

 

For whatever reason my modem/router decided to just give out during the move. I’m only a year in to my warranty and am considering getting a replacement..

Could you let us know the product’s model number.

 

SURFboard Community Moderator Team
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Sure, it’s SBG8300

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Since you are experiencing with slow/intermittent internet connection, let us know whether the problem is with wired connection or wireless connection.

If it's with wired connection, I suggest you check the cable signals, to make sure all the signals are in range.

To check the cable signals, find the link given below:

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Cable-Signal-Levels

If the intermittent internet connection is with wireless connection, let me share the link to change the Wi-Fi channels and monitor the same for next 24hours of time.

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Changing-the-Wi-Fi-Channel

 

SURFboard Community Moderator Team
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