Community Forum

Modem/router speed question

Xfinity Forum Archive
About the archive project

Xfinity Forum Archive...

This is an archived section of the community.

Content in this area has been identified as outdated or irrelevant.

This change was done in an effort to make the forum easier to use and to keep only the most helpful and recent content active.

Post your questions in the Xfinity Community

Frequent Visitor

Modem/router speed question

So after getting several emails and phone calls from Comcast saying my modem was out of date (Motorola SB5101), I decided to upgrade it.  I bought a Motorola S6141.  I also thought I might need to replace my router (Linksys E1000) with one a friend was no longer using (Belkin N150), though I wasn't sure if that was an upgrade or not.  But I figured I could try them both out.


I got the new modem installed and working, with a good deal of help from Comcast (there was a problem with authenitification).  Prior to changing modems, I ran two speed tests; one at and one at  The results were similar (download about 25-28 mpbs, upload about 11 mpbs).  After installation of the new modem, I retested several times and in three different configurations (the new modem with either router and the modem directly connected to my laptop).  My results were all over the place.  With the modem directly connected to the laptop, the comcast speed test showed 92 mpbs.  Other tests using the router resulted in anywhere from 30-75 mpbs, usually closer to 30 than 75.  Also, the higher ratings were invariably from the comcast speed test; was consistently in the 30-50 range. 


So, I have a few questions.  First, did I waste my money on a new modem?  It doesn't seem like I'm getting much more out of it than my last one.  Did I buy into Comcast's hype? Second, would a better router be worth it?  Or should I just compare the two I have more thoroughly and use the better one of the two I have?  Lastly, I'm suspicious that comcast's test appears to always give better results than the independent one (even though it seems to use the same technology).  Should I be?


Thanks for reading what has turned out to be a much longer post than originally intended.

Problem Solver

Re: Modem/router speed question

okay try and give some answers.


#1 No not really, upgrading to a DOCSIS3 modem supports higher speeds. It also has more channels to bond which will improve performance during periods where your segment is congested.


#2 Depends on what you are connecting on wireless side, always better to have a fatter (gigabit) wired pipe to modem for bandwidth, but if everything you are connecting is A B G or N150 there is little point buying the latest greatest router with dual band N900/AC2700 they wont make the connection any faster on old NICs. An inexpensive N300 or dual band N600 would give better signal coverage for far less cost (just remember the gigabit wired). The higher speed routers tend to have a better/stronger signal and improved filters for interference.


#3 Well of course Cc is going to give better speeds, it is going to a closer server, the other version of test is pinging a router some number of hops further out.

You might goggle ShaperProbe and see what numbers are like with that.


Wired connections will generally give faster speeds than wireless. Partly due to one less step in translation, and also the interference signal strength and configuration of wireless connections plays a part. Each wired connection gets it's own slice of the bandwidth pie, all the wireless connections share the same one pretty much.