Are you connecting on the 2.4 or the 5g?
Generally, Kiwi is right though.. the wireless isnt great on any of the built in ones.
To get decent wifi/coverage, you really need to go with a decent 3rd party router.
Even with them, there is a big difference between the $40 and the $150 ones.
Can you log into the modem, navigate to the STATUS....DOCSIS WAN tab, copy the downstream and upstream tables and paste them into this thread. They contain the signal levels and signal to noise ratios for the RG-6 cable that connects to the modem. It sounds like you might have a signal issue on the go. If you go to this page and look at tehe DPC3825 section, you will see what the ideal signal levels and signal to noise ratios would look like:
The downstream signal levels aren't too bad. They aren't great, but it probably not time to call for a tech just yet. I believe the cut-off is -6 dBmV before a tech will be sent out. The signal to noise ratios are fine and your upstream signal levels out of the modem heading back to the local node aren't too bad either.
Do you see problems with wired or wireles performance or both? For the wireless network do you use a 2.4 Ghz network primarily? I'm trying to remember if the 3825 has a 5 Ghz capability.
Are you in a house, condo, apartment, etc.?
If the problem is with wifi, the first thing to do is check out your wifi environment. The link below is for the last freebie version of inSSIDer, which can monitor both 2.4 and 5 Ghz bands. It doesn't display 802.11ac networks which are becoming more common, so it doesn't present the whole picture in the 5 Ghz band, but its pretty close. There is a new version out which is now a pay version $20 U.S., and worth buying if you have a 5 Ghz capable laptop and you happen to use 5 Ghz networks, including 802.11ac networks.
Load this on your laptop and have a look at the graphical display to see where your network sits in relation to the other networks from nearby routers. You might see that you are in a fairly crowded 2.4 Ghz area, in which case it might be rather tough to solve this. Perhaps one of your neighbours has brought home a new modem or router and has a network up which is competing with yours. By looking at the graphical display, you might be able to see another channel that you could use that isn't occupied, or, if it is, the power levels of the existing network on that channel is lower than where you are now;
http://www.techspot.com/downloads/5936-inssider.html
The cable that runs from the wallplate to the modem is an RG-6 cable. You can usually pick one up at a local store. When you have installed that cable can you repost the signal levels again?
