Question Can I hardwire pc to modem and also use wifi router for other devices? wifi stops seeing internet when I do

Jan 29, 2020
I have Xfinity, should have speeds up to 600Ghz. I have a new Arris T25 voice modem and a new tp-link Archer A6, ac1200. New cat6 ethernet. My wifi is OK. I have gotten up to 300, one time I got 450 direct wired to the modem. Usually wifi is in the 100's though. I want to try having my laptop wired DIRECT to the modem, and then also having a wifi network. The modem has 2 ports, but when I connect one to the laptop the wifi will not work. The wifi will not work on ANY device connected to the router if the pc is wired to the modem. When I wired the pc to the router I got the same speed as on wifi and the same network name. Should the speed wired to the ROUTER be the same as the speed wired directly to the modem.

On Ethernet alone I get unidentified network. I have to restart everything to switch it. I have a Lenovo yoga 710 which has an intel AC3160 wfi card and a realtek PCI GBE . I don't understand if I should be enabling the Local area connection or the "ethernet" when I want to use the PC as wired. I'd like to be able to use it wired at the desk, but be able to use wifi if I leave the room. I want the best wifi speed I can get.

Is there something I'm missing that when I hardwire to the modem my wifi network goes out? The pc lists the network, but with "no internet"

I don't know what I have screwed up here. I have restarted everything so many times. Does the laptop have to be restarted everytime, because it is not quick!!

Finally, I just read the the modem may need 2 ip addresses and I'd have to ask Comcast. Could that be it? Will they give me 2?
First, internet speeds come in Mbps (megabytes per second) not Ghz (gigahertz).

If you are paying for that high of a speed then you should be getting it. If there is nothing wrong with your modem, then it should be able to handle speeds up to 1Gbps. Well over what you say you should get. The same goes for the router.

If set up correctly, you should be able to connect the router for WiFi access while still connecting any device via Ethernet to the modem. Or even direct to the router. This should not change the speed of the Ethernet connected device. Not unless, again, there is something wrong with the modem/router, the settings for the modem/router have been altered to create limitations, or your ISP is the cause. Personally I would be leaning towards it being the ISP.

Now getting lower speeds over WiFi is pretty normal. Depending on how many devices are connected, how far from the WiFi it is trying to connect, etc.

I suggest you start by logging into the modem and look at its settings to see if you find a problem there.
Jan 29, 2020
I found out that to use both ports on the back of the modem I need to have 2 ip addresses, and apparently xfinity doesn't give you more than one unless you are a business (and pay for a bundle of 5) . So my only option is wired to the router. Apparently, as you said, I "should" be able to use the router and direct connect as well, bu Comcast doesn't think so....

JUST tried a new speedtest from OOKLA , it prompted me to use a speedtest from the windows store and it showed much higher speeds. About 300 on wifi and 416 wired to router. That's more like what I expected. That wifi speed is all I need at that rate. I'm still curious about speeds direct from modem, but since I can't use the router at the same time I guess it doens't matter what speed the modem is.
I don't get why they are telling you that you need to use both ports, unless that is the way your modem is actually set up. Some can only reach certain speeds with more than one connection, which would be rather costly.

Sadly many of the speed test sites are actually given priority access by some ISPs. So the info they give may not be what you are getting. Personally I like to use...

There is no logical reason that you should not be able to connect a device (wired) to either the modem or the router and then connect other devices via WiFi to the router. Not unless there is something wrong with the devices or something in their settings. Unless, of course, the ISP is limiting something. Which they shouldn't be able to.

I have to say though, if you are paying for seriously high speed internet, then you should be getting it. If you aren't getting what you are paying for, then you should consider lowering the speed you pay for.

Additionally, unless you have lots of things accessing your internet connection, most people don't need speeds that high.