Ultimate 300Mbps upgrade modem question

well that's a bogus reasoning and completely ridiculous.  And I'm well aware of the approved modem list.  I was sent to the cox store to get an "approved" 16 channel modem and they don't know what I"m talking about.  How do you upgrade speeds and don't have the equipment available to support it?

Well the lack of knowledge about the new upgrade requirements just caused me to waste half a day over nothing.  I got techs telling me all I need is a 3.0 modem, I got others telling me to go rent one it's definitely available at my local store, and others that say "your market doesn't have the 300Mbps" so which is it?  What speed do I have in zip code 67211 for Ultimate

ChrisL, can you please explain these two statements:

"Because the modem has a maximum speed of about 300Mbps or so that means it won't be suitable for sustaining speeds above 150Mbps while somebody else is on the Internet."

and

"Don't forget that the modem's max rates speed isn't actually based on the modem but rather the node which is shared."

The modem doesn't know how many devices are on the network.  Granted you have a 300Mbps pipe shared with all devices on the network but why would overall bandwidth slow down if "somebody else in on"??

If you are saying the theoretical speed is not attainable, like with WiFi, that's one thing.  But I don't understand what you are saying about shared nodes.  Are you saying because of node sharing you get significantly less then the spec of 42.88 Mbps per channel?  Thanks.

I'm confused.  Are you saying if my 2 neighbors and I each subscribe to 300Mbps Ultimate, we share a 300Mbps pipe and each get 100Mbps????  I thought we each had a 300Mbps pipe at least to the local node.  This doesn't make sense since each node typically serves 500+ customers.  If all 500 were sharing one 300Mbps pipe, nobody would get any speed.

@allenP I'm just as confused as anyone right now.... after figuring out my Ultimate speeds apparently doubled with NO notification I inquired about it and talked to a total of 13 people of which I got a different answer of some sort.  I got everything from "it's not totally available now" to "all you need is a 3.0 modem" to "based on your address 300Mbps is definitely available!" to "you need a 16 channel 3.0 modem" to  a tech support chat agent attempting to send a tech.  Now I'm just saying this overall and not going to nor do I need to call anyone out as this is the "normal practice" of Cox.... but every tech support agent is undertrained or misinformed whatever you want to call it.   of ALL the internet tiers... Ultimate customers are going to be the MOST LIKELY to inquire about the upgrade that they hear about.... therefore a simple memo to all Cox reps would be useful or a employee reference whatever may be the case to refer to for the CORRECT answer.  Today I wasted half the day because I was told that 300Mbps is available and I need a 16 channel modem and it is definitely available at my local store.  I go there and they have no clue what I'm even talking about.  I swap my owned gateway out for the one I picked up that "is compatible" and get home and it doesn't make one bit of a difference for a charge of $9.99/month.  I take it back and reactivate my gateway I own after being told that I can't get the upgraded speeds on my SB6180 and what do you know.... 250Mbps but on this very thread I'm told that my modem can only handle the pipe blah blah blah... some useless lingo.... I'm getting the upgraded speeds on my current modem as my area is only 200Mbps as of now but yet I'm told by countless reps I have to upgrade to either a rental or buy a modem that I don't even need to pay the $9.99 a month OR the $99.99 to buy a modem.  I'm just really disgusted with the level of support I get as an Ultimate customer it's unsatisfactory.

I think Chris is trying to simplify the answer but at the cost of accuracy. Think of it like traffic on a highway. There is the physical limit of how many cars can fit on the road, which depend on the number of lanes, but once you start getting even close to that number, traffic becomes more of a issue. Because of this, Cox tries to work in a buffer between what speeds your technically able to get and the speeds your modem is configured for. That's why a DOCSIS 2.0 modem usally can't get above 32Mbps even though it could technically get up to 38Mbps according to the specs. 

As for what modem you need, it would either be the Arris SB6183, SB6190 or the Netgear CM500. There are other options if your open to gateways, but I wouldn't suggest them.

I understand running at 100% of capacity and with speedboost you will go over the 300Mbps max on an 8 channel modem.  But ... Chris said Sl4ck3r's area is only increasing to 200Mbps, well below the 300Mbps max.  Even with speedboost, you will only go up to about 250Mbps and, as Sl4ck3r posted, is doable with an 8 channel modem.  So, I agree, if you are getting 300 or above, a 16 channel modem is required but you can get by with 8 channels at 200 or below.  DOCSIS 3.1 is just around the corner, why update now if you don't have to?  Finally, where I'm confused is all Chris' talk about shared pipes.  Not sure his point there.