Not getting anywhere close to the internet speeds I'm paying for

First, according to Cox's list of approved modems, the SB6120 is only approved for Prefered and below for the reasons your probably seeing. Also, the E2500 maxes out 91Mbps according to this review. Not to mention it doesn't have the 10/100/1000 ports that it needs for 100+Mbps speeds. Overall I think your going to need a new modem and router to make best use of your internet.

It may be worth seeing what speed you get direct to the SB6120, in case it's just a router issue, but I suspect not. 

My bad on the modem I swore it could handle it but I guess not. On the router it says it can handle up to 100Mbps on the box even if it's only 91Mbps I would be fine with it. Even if my modem/router can't handle the 100Mbps down shouldn't it still be faster then what I had before and not the same or slower? Like I said the speed test through my Xbox One usually tested 10Mbps faster then what I was paying for on the tier that's before Premier. Now since the upgrade it's lower then before with an occasional spike in the download speed. Just before typing this up I ran 4 speed tests on my Xbox One. The first one the download was 38Mbps, the 2nd test it was 74Mbps, the 3rd one was 34Mbps and the last one was 29Mbps download. The upload stayed pretty consistent at about 10Mbps.  

Con100 said:
On the router it says it can handle up to 100Mbps

What they were talking about is the technical, theoretical, limit. The wireless on the router is rated for 300Mbps, but that doesn't mean you can connect at the speed under all conditions either. I agree it's confusing, and I think that is done on purpose by the router manufacturers.

Con100 said:
shouldn't it still be faster then what I had before and not the same or slower

You would think that, but it's also possible that Speed upgrade caused the issue, but not as you would suspect.  The act of increasing the speed in an area can create an increase in bandwidth use too, which can actually decrease the speed for you. It's is kind of hard to explain, and has to do with channel bonding and the way the modems work. I can go into more detail if you want, but if not, I will spare you the details.

In the end, all I can do is give advice to help isolate the problem. So far we don't know if the problem is a issue with the modem, router, or both. I would first bypass the router and connect directly into the SB6120, and then reboot the SB6120. If the speeds are still slow then, then you know it's not your router.

Also, it wouldn't be a bad idea to look at your modem's signal levels. They can be found here on your modems 192.168.100.1 webpage under "Signal". Copy/paste them into a reply.  If those are bad, then that should be addressed before you buy ANY new equipment. 


 

I just connected my desktop to the modem and I'm getting the speeds I pay for or close to it at 94Mbps. When I tested through my laptop I couldn't get close so I think the internet card on there isn't that good. I mean wireless it was getting less then 20Mbps and wired to the modem wasn't much better. I didn't test my Xbox One since I have a static IP setup and I don't want to touch the internet settings. Since it seems to be an issue with the router I'll look into buying a better one but I doubt I will find an affordable one so I might just end up downgrading back to the 50Mbps tier. 

Now do I specifically need to look for a Gigabit router?

Nevermind the edit post button wasn't showing up at first.