dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
1514
share rss forum feed

kucharsk

join:2001-03-30
Louisville, CO

[Speed] Speeds all over the place since 100 upgrade; anyone else

Immediately after the 100 upgrade, I saw speeds of 105 - 110 down, 20 up, but since I've seen everything from 69 - 85 down, 20 up. Every once in a while I see 100+ down again, but it's pretty rare.

Attempts to contact Comcast have met with 20+ minute hold times and promises to call me back that never come.

I posted on the Comcast Direct forum last night but haven't received a reply.

Anyone else seeing this behavior?


andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL

Re: [Speed] Speeds all over the place since 100 upgrade; anyone

With all these speed changes, the speedtest servers could be overloaded at times, or at least their own network connection speeds could be overwhelmed.


JJJohnson

join:2001-08-25
Fort Collins, CO
reply to kucharsk
I seriously doubt that the Comcast network is capable of delivering 100 Mbps speeds to all end users 24x7. It's going to depend on too many factors, including where you're connecting.

kucharsk

join:2001-03-30
Louisville, CO
Yes, but speedtest.comcast.net resides on Comcast's own network, so the influence of other factors should be minimized and only the question of internal bandwidth is at play.

Besides, I doubt Comcast's internal servers are getting hammered at say 3 AM when I've run some of the speed tests, and speed of 100+ wouldn't be restored by a modem reboot.

quesix

join:2005-12-19
Cary, IL
reply to kucharsk
I see the same myself at home, speeds from 40mbps upto 90mbps. (105/20 package speed). Likely due to network backend design or speed test site overload. Will likely improve as they get more customers on 105/20 package and upgrade backends as actual sustained usage increases.

kucharsk

join:2001-03-30
Louisville, CO
Yeah… the problem continues here.




AnonMan

@comcast.net
This isn't always going to be the speed test servers like you all think.

At the moment the cable plants only support 8 DS channels. So around 300Mbps of service.

If your node just happens to have a good deal of people on it this is the result of the shared bandwidth hitting its limit... The node could have a 1Gbps link but does no good since the coax is limited with the 8 channels currently used.

My area doesn't have many Comcast users as most are on Bright House so my speeds are great but if you have a few others with the high speed package or even just a bunch with the lower ones it adds up...

The Comcast test servers are generally on the 10Gbps backbone link so doubt it's a speed issue with them and is likely local...

Best I can suggest is make sure you have an 8 channel DS modem if you happen to only have a 4DS channel Docis 3 one and that will help solve your issue for the moment.

Docis 3.1 will solve the issue when it's rolled out next year but you got a while for that and even after that the issue can re-appear if the speeds are kept updated like this.

gr82cu

join:2013-04-08
Dickson, TN
reply to kucharsk
I personally never use the CC speed test site in the first place. It has been wildly inaccurate for me in the past. All of them have their downside but I have had the best luck with testmy.net .

kucharsk

join:2001-03-30
Louisville, CO
I use the CC speed tests as they're the only one (in my experience) Comcast Support considers "official."

How many channels does an SB6120 support? That's what I have.

rody_44
Premium
join:2004-02-20
Quakertown, PA
Try another speed test. Or better yet a real world download. Speedtests are not very accurate when you get up to 100 Mbps speed.


C_Chipperson
Monster Rain
Premium
join:2009-01-17
00000
kudos:3

1 edit
reply to kucharsk
said by kucharsk:

I use the CC speed tests as they're the only one (in my experience) Comcast Support considers "official."

How many channels does an SB6120 support? That's what I have.

I was on the same modem, it supports 4 downstream and 4 upstream channels. I bought a Zoom 5341J 8x4 modem a couple weeks ago after the speed upgrade, and I consistently see ~115-120mbps down and ~20mbps up. With the SB6120 it would vary quite a bit. So I think having the additional downstream channels on the Zoom modem helps stabilize the speed.

Edit, here is a speed test I did with my 5341J (Over WiFi believe it or not!)



And a test with my SB6120 a few weeks ago, but same time of day for comparison:



AnonMan

@comcast.net
Sounds like indeed the channel issue.

Get a new 8DS channel modem and I bet your issue is gone for the time, unless too many in your area upgrade speeds lol.

I personally have the Cisco DPC3008 and love it. Had issues few years back but been great after fw fixes. Others like zoom, just get whatever you can get a good price on. Almost every 8 channel modem uses the same internals for the most part. I think only 2 chipsets exist for them so the rest is just layout changes and firmware.

As for speedtests sites, it depends on location really. If you have a Comcast one near you the speeds should be more accurate vs. any others as all data would be on net, but if it's a bit far it might not be accurate. I have 3 Comcast ones on net near me all under 15ms and all on 10GB back links and all accurate. some of the speedtest.net ones are owned by ISPs also fwiw. Other tests sites the accuracy depends on load as even if they are on 10GB back link they require you to travel through other links to get to them that might have load vs. if a local Comcast one it would be local on net and not travel far thus risk of load lower.

rugby
I think I know it all.
VIP
join:2000-09-26
Plainfield, IN
reply to kucharsk
I can't sustain over 80Mbps on my 6120 either, I have a Zoom 5341 I picked up at Best Buy I'm going to get Comcast to provision for me if they can ever figure out what happened to my account when they moved my service.


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:10
said by rugby:

I have a Zoom 5341 I picked up at Best Buy I'm going to get Comcast to provision for me if they can ever figure out what happened to my account when they moved my service.

Is that a 5341J (note the *J* model). If not, it is a lateral move from the 6120. Only 4x4 capable. The J is 8x4.

rugby
I think I know it all.
VIP
join:2000-09-26
Plainfield, IN
said by EG:

said by rugby:

I have a Zoom 5341 I picked up at Best Buy I'm going to get Comcast to provision for me if they can ever figure out what happened to my account when they moved my service.

Is that a 5341J (note the *J* model). If not, it is a lateral move from the 6120. Only 4x4 capable. The J is 8x4.

Yes, it is a J model. Sorry, I left that off in my post.

devnuller

join:2006-06-10
Cambridge, MA
reply to kucharsk
How's your Internet experience?

At 100M speed tests become less reliable. Is it that important to call in about?


AnonMan

@comcast.net
If it wasn't important to them I would imagine they would downgrade to blast and get similar for half the price

I have no problem with speed test sites using 300+M connections. You just got to know how to pick the correct ones.


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:10
said by AnonMan :

I have no problem with speed test sites using 300+M connections. You just got to know how to pick the correct ones.

Would those be the ones that tell a person exactly what it is that they WANT TO HEAR ?

kucharsk

join:2001-03-30
Louisville, CO

1 recommendation

reply to kucharsk
Just got back from Best Buy where I picked up a Motorola SB6141 (my SB6120 has been good for me, so I decided to go with another SurfBoard modem.)

Now I'm eight channel bonded and:



Chris 313
Come get some
Premium
join:2004-07-18
Houma, LA
kudos:1
Reviews:
·AT&T U-Verse
·Vonage
·Comcast
·Comcast Digital ..
said by kucharsk:

Just got back from Best Buy where I picked up a Motorola SB6141 (my SB6120 has been good for me, so I decided to go with another SurfBoard modem.)

Now I'm eight channel bonded and:


Nice that you made the upgrade. Whether or not your speeds stay that way, you've got yourself an 8X4 modem and will be better for it when Comcast gets everything straightened out.

kucharsk

join:2001-03-30
Louisville, CO
I'm hopeful.



AnonMan

@comcast.net
As I said, most of these issues are congestion on channels.

The Comcast speedtest are all on-net and I assure you NONE of them are even half way near capacity.

While 4 DS can handle around 150M the problem is those same 4 have many other people on them. Having 8 gives it more headroom. The issue can re-appear if another speed bump happens to everyone, additional people on your node sign-up that are not customers, or some uses more bandwidth or upgrade to faster and do so.

Remember, each node only gets 8 DS channel which is approx. 300M bandwidth for every home that it feeds. Not really a lot when you take into account a node can have 50 houses and in some cases more, some less... A few people can bring it to a crawl. The business is run on overselling and having customers use bandwidth when others are not, combined with that most people don't use what they have... Web hosting is the same, you think all those uncapped 1GB internet colo's you see online have unlimited BW? nope they just know some use it some don't... So sell the idle...

Anyway, glad to see the new modem solved the problem.

kucharsk

join:2001-03-30
Louisville, CO
Definitely looks that way; thanks all for your help.