I don't know how long this has been going on but this past week I tried to play some games on the PC there was a terrible connection, bouncing through the games or sometimes dropping connection. I ran a few tests on DSLreports and the ratings for the connection were all pretty bad (I can post them later tonight from home).
I also tried the downstream/upstream test in the forums and the levels did not seem out of the ordinary (again, I'll post full details later). My setup is a little complex in that I have a few cat5 ports throughout my house so I have the Cisco DPC3825 modem in my basement with 4 ethernet lines going around the house, 1 of which goes to a TPlink n750 on the main floor office where my PC is and is acting as a wireless AP (2.4GHz and 5GHz networks).
The Cisco router handles the DCHP and also has a wireless network for the basement (2.4GHz). I don't think it is an issue with how I have the routers connected because I ran the DSLreports tests connected to both routers and there was little difference.
Is this something a tech would need to come out for or is there something else I can do to try to diagnose?
What you can do, just to check the cable signal levels is to log into the modem, navigate to the STATUS... DOCSIS WAN page, copy the downstream and upstream tables and paste them into the thread. Those tables contain the signal levels and signal to noise ratios. If there's a problem with the signal levels, it will show up in the tables. From there, if necessary, its just a matter of a call to tech support for a modem signal check and an appointment for a tech to determine what the problem is and correct the issue. The external cable and connectors don't last forever and every once in a while a tech has to replace one or both, depending on their condition. First matter is the downstream and upstream tables.
If you look at this thread, specifically the DPC-3825 section, you can see what the ideal signal levels would look like. How they actually look depends on the condition of the external cable and connetors.
The downstream are good, the upstream are elevated above their usual 36 to 40 dBmV range. At 46 dBmV, I suspect that tech support will send a tech out to see what the issue is. Those levels are a little unusual in that they are both elevated. Typically for a home, the downstream levels drop below 0 dbmV and the upstream out of the modem is increased to compensate for cabling and connector issues. If there is a signal amplifier in the system that could account for the levels.
Just an update, I talked with a tech and after running a few tests he said the signal levels all looked perfect but couldn't really find an explanation. As a final resort he recommended trying a factory reset to see if that solved it. It didn't but I tried putting the Cisco gateway back into bridge mode and the problems went away. This isn't ideal since I would like to put my new NAS down with the gateway in the basement to keep it out of the way and to use the stronger wireless signal for my basement entertainment unit, but I don't think I'll be able to do this with the gateway in bridge mode. I guess I'll try to exchange the gateway.