Internet speed vs Modem speed

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Saving$
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Internet speed vs Modem speed

Post by Saving$ »

Can someone explain how the cable modem "up to speed" is related to the internet speed?

My modem is rated "up to" 300 mbs. I had internet "up to" 25 mbs and it worked fine. Comcast is upgrading my internet to "up to 80 mbs" and suggests I need to get a new modem.

Since 80 is less than 300, why would the 300 mbs modem not handle it? Would I notice a difference with a faster modem?

For reference there is usually only 1, max 2, devices actively using the internet (ie 2 browsing, 1 browsing + 1 watching Netflix). There are a few other devices connected, such as one or two cell phones and an Ipad but not doing anything except receiving emails and calls.
02nz
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Re: Internet speed vs Modem speed

Post by 02nz »

No you don't need a new modem. It won't be faster. Unless you have an ancient modem (and you do not) it will never be the bottleneck for your internet connection.

Comcast would just as soon that you got a new modem, because maybe you'll rent it from them and pay $5 or $10/mo or whatever, which is a huge moneymaker for them on something that costs them maybe $30.
KT785
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Re: Internet speed vs Modem speed

Post by KT785 »

Depending on how old your current modem is its specs, you may actually need to upgrade to realize the higher speeds from your provider. I had to upgrade in 2018 and noticed significant boost in performance.

I should note that I own my own router and always have . . . and would recommend you do the same.

My current router is an ARRIS SURFboard SB6190; currently have Spectrum but previously had Comcast which is when I discovered the old modem (SB6121) was a factor in my below advertised speeds.

KT785
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Saving$
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Re: Internet speed vs Modem speed

Post by Saving$ »

02nz wrote: Mon Dec 16, 2019 5:50 pm No you don't need a new modem. It won't be faster. Unless you have an ancient modem (and you do not) it will never be the bottleneck for your internet connection.

Comcast would just as soon that you got a new modem, because maybe you'll rent it from them and pay $5 or $10/mo or whatever, which is a huge moneymaker for them on something that costs them maybe $30.
Thanks.
With cable modems is it better to have a modem/router combined or separate devices?
The combo I currently have does not allow a guest network. I may not be understanding this correct but gather if I ever connect a device that can be accessed via the web (such as a security camera) it should be connected to a separate guest network, and I'd also move the Roku. If that understanding is correct, I'm in the market for a new modem / router anyway. Just trying to understand what "rating" or speed I need.
02nz
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Re: Internet speed vs Modem speed

Post by 02nz »

Saving$ wrote: Mon Dec 16, 2019 6:09 pm
02nz wrote: Mon Dec 16, 2019 5:50 pm No you don't need a new modem. It won't be faster. Unless you have an ancient modem (and you do not) it will never be the bottleneck for your internet connection.

Comcast would just as soon that you got a new modem, because maybe you'll rent it from them and pay $5 or $10/mo or whatever, which is a huge moneymaker for them on something that costs them maybe $30.
Thanks.
With cable modems is it better to have a modem/router combined or separate devices?
The combo I currently have does not allow a guest network. I may not be understanding this correct but gather if I ever connect a device that can be accessed via the web (such as a security camera) it should be connected to a separate guest network, and I'd also move the Roku. If that understanding is correct, I'm in the market for a new modem / router anyway. Just trying to understand what "rating" or speed I need.
Separate is better. Cable modems last forever. I have one from 2003 that still works fine, although my current ISP refuses to allow it because it's "too old." And the technology changes very little. Wi-fi routers on the other hand rarely last much longer than 3-4 years, and there's a new wi-fi standard every 5 years or so (backward compatible, but with advantages that may make you want to upgrade.) So most people end up replacing their routers far more than they need to replace cable modems. Dedicated routers tend to have more advanced features (like the guest network you're looking for). And if you want to go with a mesh network you'll have to get a separate modem, not aware of any with the modem built-in.
Topic Author
Saving$
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Re: Internet speed vs Modem speed

Post by Saving$ »

I have a fairly new (2 year old?) router that I could reconnect.

Would this be a decent cable modem?
https://www.amazon.com/ARRIS-Surfboard- ... ER&sr=1-10
KT785
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Re: Internet speed vs Modem speed

Post by KT785 »

Saving$ wrote: Mon Dec 16, 2019 6:39 pm I have a fairly new (2 year old?) router that I could reconnect.

Would this be a decent cable modem?
https://www.amazon.com/ARRIS-Surfboard- ... ER&sr=1-10
I’d go with the SB6190 like I have (noted above); it’s on sale for just a bit more today on Amazon: https://www.amazon.com/dp/B06ZZGXJKM/re ... -Db51BBHYQ

KT785
02nz
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Re: Internet speed vs Modem speed

Post by 02nz »

Motorola SurfBoard modems are fine. Any one will work with your ISP as long as its DOCSIS 3.0. You'll never notice a difference between any of them in actual use.
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RickBoglehead
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Re: Internet speed vs Modem speed

Post by RickBoglehead »

Saving$ wrote: Mon Dec 16, 2019 6:39 pm I have a fairly new (2 year old?) router that I could reconnect.

Would this be a decent cable modem?
https://www.amazon.com/ARRIS-Surfboard- ... ER&sr=1-10
Comcast has an approved modem list, and they can require you to remove outdated modems. Outdated modems inefficiency use bandwidth as compared to newer modems, and this impacts other customers.

Here is the website to see if a modem is currently approved: https://mydeviceinfo.xfinity.com/customerinfo

Yes, you want many things connected on your Guest network. Many internet devices like thermostats, appliances, cameras, etc. should ideally be on a guest network. Why? These devices often store your WiFi password, and of course have access to your network. Many have outdated firmware that at some point is hackable, and the hacker now has access to your network. In addition, many people are not bright, and never set a userid and secure password on their devices. If the device is hacked on your main network, all of the data sitting on your PCs, tablets, and phones is potentially at risk. If they hack a device that is on your Guest network, the worst they can do is screw around with those devices, like raising or lowering your temperature.

In addition, many devices store information in the cloud. Thermostats, garage door openers, TVs, etc. When they ask for your name to "register", provide a false one. Daffy Duck at 432 Elm Street might own the thermostats.
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DiamondplateDave
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Re: Internet speed vs Modem speed

Post by DiamondplateDave »

02nz wrote: Mon Dec 16, 2019 6:15 pm Cable modems last forever. I have one from 2003 that still works fine[...]
I first got broadband (Earthlink over Time Warner) in 2002. The cable modem they provided got flakey and needed to be rebooted every day or two about 2008. After some go-around with the tech support (they don't support Linux-Mac-nor versions of Windows ending in odd build numbers or such) and having to basically lie that I "had just re-installed Windows", they sent a tech out. He replaced my cable modem, and also did something to the cable. Everything fine for about another 5-6 years. Then, similar problem. I lived with it for a while rather than deal with the tech support "diagnosis". Finally got fed up. Surprise, they told me to bring the cable modem to their service center and exchange it. So, I did so on the way somewhere in that direction. Upon getting home that night about 10:30, I went to set up the new modem, only to find out the AC brick they gave me in the bag with the modem didn't fit. :oops:
So I had to scrounge through my junk box and find a suitable supply and cut the wires and splice them to reverse the polarity. Then back the next day to return the modem and wrong PS and get another.
So, my cable modem mileage varies. For OP, I would recommend investing in a good quality cable modem and a separate router as recommended. Also second the guest network for IoTs.
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JoMoney
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Re: Internet speed vs Modem speed

Post by JoMoney »

Unless you have multiple users, on different computers/devices, streaming high definition video.... all at the same time.... You're unlikely to notice much if any difference.
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Topic Author
Saving$
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Re: Internet speed vs Modem speed

Post by Saving$ »

KT785 wrote: Mon Dec 16, 2019 6:49 pm
Saving$ wrote: Mon Dec 16, 2019 6:39 pm I have a fairly new (2 year old?) router that I could reconnect.

Would this be a decent cable modem?
https://www.amazon.com/ARRIS-Surfboard- ... ER&sr=1-10
I’d go with the SB6190 like I have (noted above); it’s on sale for just a bit more today on Amazon: https://www.amazon.com/dp/B06ZZGXJKM/re ... -Db51BBHYQ

KT785
Went with the SB6190 and it is working out very well. THANK YOU.
GeoffD
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Re: Internet speed vs Modem speed

Post by GeoffD »

I worked for cable modem companies for a decade so I’ll give it a shot:

The data over cable standard, DOCSIS added a feature called channel bonding with DOCSIS 3.0. This was around 2008. It let the cable modem use multiple channels simultaneously. The early D3.0 modems supported 4 downstreams. You could get 105 megabit/second out of them for most customers out in the field and 150 megabits/second in an ideal lab environment. 8 downstreams is a 300 megabit/second D3.0 modem. A 16 downstream modem 600. A 32 downstream could do a gigabit though a gigabit Ethernet cable will only give you about 920 due to overhead of the Ethernet standard.

DOCSIS 3.1 added one very wide channel and you can get a couple gigabit out of it if you have multiple Ethernet ports and WiFi in it. The newest ones have 2.5 gigabit Ethernet. That is the latest and greatest in the field now.

The next emerging DOCSIS standard will let you do gigabit speeds on the upstream. This gives equivalency to fiber. It’s now called DOCIS 4.0.

Any modem older than DOCSIS 3.0 does not support IPv6. The cable operators ran out of IPv4 addresses so they now manage cable modems with IPv6. That is why Comcast won’t let you use an old D2.0 or D1.1 modem. They manage 40 million cable modems on their plant and their management system is all IPv6.

As a practical thing, an old D3.0 4x1 modem at 100 megabit per second will stream a Netflix 4K video or two just fine.

I have 3 residences that are all Comcast. I use 16x4 modems and Netgear dual band AC WiFi routers connected with gigabit Ethernet. I have no interest in paying Comcast $15/month rental fee. Unless it says Arris on it, all retail modems use the same Broadcom chip and almost always use the same Broadcom reference design. Broadcom supplies the software and no vendor touches the DOCSIS part. They’re all certified at CableLabs. Comcast then tests them for a big test fee and puts them on their approved list. I did one of those projects with a 16x4 about 5 years ago.

For most people, a $57 on Amazon Netgear R6230 WiFi router and a $40-$50 8x4 or 16x4 modem on Amazon will work fine. With the 100 megabit speed tier at Comcast, that will run the big panel on your wall and some web surfing just fine. What matters is to buy a router that supports gigabit Ethernet. The cheapest ones only support 100 megabit Ethernet so you’ll only get about 90 megabit down the Ethernet cable between the modem and the router.

I used to work for SMC which is now out of the cable modem business. I run the SMC 16x4 D3CM1604. It was built by Castlenet in Taiwan. There are shipping pallets of them with a 3rd party retailer that are cheap on Amazon. $39.50. That’s the best price you’re going to find on a 16x4 unless it’s a refurb.
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Re: Internet speed vs Modem speed

Post by lazydavid »

The number of channels is the most important bit. If you're in a congested area, you want more channels than your neighbors, even if you don't need anywhere near the bandwidth that some of these newer modems provide. Why? Cable internet is a shared medium, so at busy times the "low" channels get saturated first, and you can get starved for bandwidth. Everybody uses the first four channels, because even very old modems support them. So if that's all you've got, the quality of your connection is dependent on how much bandwidth everyone else in your neighborhood is using.

On the flipside, if you've got a 32-channel modem, chances are you've got channels 17-32 almost entirely to yourself. So congestion doesn't really affect you. I definitely would not consider buying a modem with fewer than 16 channels today, even if you only have a 50 or 75Mbps connection. I use a Surfboard SB8200 (32 channels), and have no problem getting more than my provisioned speed at any time of day.
Hogan773
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Re: Internet speed vs Modem speed

Post by Hogan773 »

This is all very interesting to me because I am struggling with what to do on buying a new modem (or not)

Reason is, I have been getting very consistent 120mbps download speeds for several years, yet Comcast advertises that they bumped up my "Blast tier" to 200mbps sometime last last year I think. I tested and thought maybe the constraint is my Netgear R7000 wifi router, but when I plugged the cable modem into the PC directly I still only got the 120mbps.

I have Arris TM822G which I own. It is apparently 8x4 modem. Comcast lists it as "up to 300mbps approved" which is why I'm confused. If I got a 16x4 or even higher XX x 4 modem, will my speed rise? Is the 8 downstream channels somewhat capping my speed to 120 even though Comcast thinks my modem should be good for 300mbps? I have tried rebooting the modem and hard reset to force it to update firmware, too, and it didn't seem to change anything.

Thoughts? Unfortunately I will need to spend more $$$ if I buy a replacement because I would need to buy one that has voice telephony too, and those are more expensive. As a tinkerer I am always interested in getting "more" speed etc, but the other thing I need to figure out is whether I really need a faster internet as 120mbps doesn't seem to limit me any way. It is more the feeling that I am supposed to be getting 200mbps that makes me want to find a way to get it!
BuddyJet
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Re: Internet speed vs Modem speed

Post by BuddyJet »

Hogan773 wrote: Wed Mar 11, 2020 12:27 pm This is all very interesting to me because I am struggling with what to do on buying a new modem (or not)
.......


Thoughts? Unfortunately I will need to spend more $$$ if I buy a replacement because I would need to buy one that has voice telephony too, and those are more expensive. As a tinkerer I am always interested in getting "more" speed etc, but the other thing I need to figure out is whether I really need a faster internet as 120mbps doesn't seem to limit me any way. It is more the feeling that I am supposed to be getting 200mbps that makes me want to find a way to get it!
FWIW, I prefer my voice through a separate VOIP adapter. Voice on the modem usually locks you to the cable voice plan rather than the cheaper VOIP providers. I use the OBI202 voice adapter with Anveo and Flowroute as providers.

My cost for voice through ATT was $40/mo and $10/mo through Anveo.
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Hogan773
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Re: Internet speed vs Modem speed

Post by Hogan773 »

BuddyJet wrote: Thu Mar 12, 2020 9:14 am
Hogan773 wrote: Wed Mar 11, 2020 12:27 pm This is all very interesting to me because I am struggling with what to do on buying a new modem (or not)
.......


Thoughts? Unfortunately I will need to spend more $$$ if I buy a replacement because I would need to buy one that has voice telephony too, and those are more expensive. As a tinkerer I am always interested in getting "more" speed etc, but the other thing I need to figure out is whether I really need a faster internet as 120mbps doesn't seem to limit me any way. It is more the feeling that I am supposed to be getting 200mbps that makes me want to find a way to get it!
FWIW, I prefer my voice through a separate VOIP adapter. Voice on the modem usually locks you to the cable voice plan rather than the cheaper VOIP providers. I use the OBI202 voice adapter with Anveo and Flowroute as providers.

My cost for voice through ATT was $40/mo and $10/mo through Anveo.
I have a Triple Play contract with Comcast where the phone part is hardly any more than I could have gotten for just TV and internet so I didn't want to monkey around with yet another provider in the mix
BuddyJet
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Re: Internet speed vs Modem speed

Post by BuddyJet »

Comcast approved modems may vary by zip code but you might check out the arris tm822g on eBay for about $40. Will work at 200 meg and offers voice.

From a quick ebay search, this listing looked good but I don’t know seller or modem.

https://www.ebay.com/itm/Arris-TM822G-C ... bb2a45ad33
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