CM1200 Modem Using Any Single Port?

[ITGL72]

On my CM1200 with a PC connected directly to it on port 1 I'm getting about 100 Mbps but if I connected it to port 2 on my CM1200 the speeds jump to about 250 Mbps.

Is the modem designed to be able to use any of the 4 ports as long as its a single port being used? I tried port 2 on an off chance to try to troubleshoot. I did not try using only port 3 or 4.

Is it possible Port 1 became damaged? I'm wondering if I need to have xfinity look at the settings again for my account and that modem.

I'm signed up for 1.2 Gbps download but something is off. 

[plemans]

have you tried more than 1 device? 

And more than 1 cable? 

I've seen some sketchy cat 5e cables. 

[ITGL72]

Yes, I've tried connecting to 3 different computers in my house, using different cat5e cables too.

Last night I tried testing connections from all 4 ports, connecting to port 4 was the fastest but is usually around 200-300 Mbps, far from my 1200 Mbps package speed. 

[FURRYe38]

I recommend trying CAT6 lan cables. Would perform better than 5e. 

Please post a copy and paste of the modems connection status page.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

[ITGL72]

Signals pasted at this link.
https://pastebin.com/ex03QtSw

I've got my hands on some cat6 cable and will try again.

[plemans]

signals don't look to bad. 

What computer do you have connected you're testing with? 

What website are you testing on? 

[ITGL72]

I'm using DSL Reports, Fast.com, SpeedTest.net, and the Xfinity speed test site. They always vary which is expected but sometimes you wonder.

I have two different tower PCs that I connect via cat6 ethernet ports. 

Anyway I had a tech over yesterday and the signal coming into the house from the street seemed fine with nearly 1000 Mbps coming to the modem.

So, I'm swapping out hardware later to the Netgear wifi-router-modem combo device because on top of all this the drop from the modem to the netgear r7000p I hooked up earlier in the week is quite a bit. Turned Armor off, QOS disabled, says no firmware updates needed but it gets between 250 350 or lower Mbps at the switch ports. Thats using different cat6 cables, computers, different port orientations.

[FURRYe38]

For best and more accurate speeds test results, try using Ooklas installable speed test app on your wired PCs. 

DSLR has never given me accurate results and speed testing with web page based test sites, I've found that some web browsers can effect speed results as well.