What ISP speed would justify a Docsis 3.1 Modem?

[TomAddison]

I'm about to sign up with Comcast for 75mbps, but I don't want to rent a modem. So I'm trying to decide between a Docsis 3.0 an 3.1 modem.

Everyone seems to say that 3.1 is only worth it if you are exceeding 1gbps, which obviously my internet speed will be no where near.

However I've also read that 3.1 will improve your internet quality at any speed.

So it is worth the extra $100ish to get the Docsis 3.1 modem or would I be wasting my money since I'm only using 75mbps?

 

[Dunlop0078]

DOCsIS 3.1 will improve your internet "quality" at any speed? What does that even mean? I dont think there is any truth to that. DOCSIS 3.1 not full duplex will handle 10gbps down and 1-2gbps up. DOCSIS 3.0 will handle 1gbps down and 100mbps up. So no you do not need a 3.1 modem and it is not worth the money unless you plan to upgrade your internet to something that will make use of a 3.1 modem in the near future.

 

[kanewolf]

Comcast will have a list of recommended modems for each speed tier. Their recommendation may be 3.1 because they may have features that they require from the modem that are only available on 3.1 hardware.

 

[TomAddison]

Comcast will have a list of recommended modems for each speed tier. Their recommendation may be 3.1 because they may have features that they require from the modem that are only available on 3.1 hardware.

Yeah, that was one of the reasons I was asking because they recommend both 3.0 and 3.1 so I wasn't sure if there was a benefit to getting 3.1 with my service.

 

[Solandri]

No real benefit except for higher speeds. Even with the DOCSIS 3.0 modems, you have to be careful to read the modem specs. The way these modems work is that they communicate with the cable company over multiple "channels" simultaneously. 3.0 modems which comply with the DOCSIS 3.0 spec still vary in the number of channels they support.

The Motorola SB6121 is only 4x4 channels (4 channels down, 4 channels up), which limits it to about 170 Mbps max. The SB6141 however is 8x4 channels (8 down, 4 up), so it can manage about 340 Mbps down. (These are theoretical speeds. I'd expect closer to 120-150 and 250-300 Mbps respectively in real-world use.) The DOCSIS 3.1 SB8200 is 32x8 channels.

Realistically though, how many years do you think it'll be before you exceed 300 Mbps? I'm pretty tech-savvy and I don't come anywhere close to needing the 200 Mbps I'm getting. I mean it's nice when I'm prepping a build and there's 1 GB of updates to download. But in those cases I usually just leave the computer downloading and work on something else or go make a sandwich. By the time I need to upgrade from my SB6141, there will probably be 10 gigabit fiber Internet connections which will require completely different hardware. So any money I could've spent on a DOCSIS 3.1 modem would've been wasted.

 

[TomAddison]

No real benefit except for higher speeds. Even with the DOCSIS 3.0 modems, you have to be careful to read the modem specs. The way these modems work is that they communicate with the cable company over multiple "channels" simultaneously. 3.0 modems which comply with the DOCSIS 3.0 spec still vary in the number of channels they support.

The Motorola SB6121 is only 4x4 channels (4 channels down, 4 channels up), which limits it to about 170 Mbps max. The SB6141 however is 8x4 channels (8 down, 4 up), so it can manage about 340 Mbps down. (These are theoretical speeds. I'd expect closer to 120-150 and 250-300 Mbps respectively in real-world use.) The DOCSIS 3.1 SB8200 is 32x8 channels.

Realistically though, how many years do you think it'll be before you exceed 300 Mbps? I'm pretty tech-savvy and I don't come anywhere close to needing the 200 Mbps I'm getting. I mean it's nice when I'm prepping a build and there's 1 GB of updates to download. But in those cases I usually just leave the computer downloading and work on something else or go make a sandwich. By the time I need to upgrade from my SB6141, there will probably be 10 gigabit fiber Internet connections which will require completely different hardware. So any money I could've spent on a DOCSIS 3.1 modem would've been wasted.

Thanks for the explanation!