Can you try a speedtest using an ethernet connection to a pc or laptop using the speedtest.net Toronto Telus server and let me know what the results are. That will give me some idea of what the modem will run at via ethernet and what to expect for the wifi.
Can you also have a look at the following thread from tonight which is very similar and let me know what you see with the inSSIDer application:
Its always possible that there is a problem with the modem. I would have expected similar performance via wifi as you saw with the previous modem, but having a look at the ethernet numbers and possibly an inSSIDer image might explain some of this.
Have you checked the bandwidth settings for the 2.4. and 5 Ghz networks? They are available for the CGN3ACSMR running V220.127.116.11, so, I'm hoping that they are available with the current firmware version that you have loaded. Also ensure that the encryption is set to WPA-2 AES only for both networks. Setting the encryption with TKIP will result in 802.11g rates which is 54 Mb/s max. TKIP, WEP and WPS should no longer be used as they are not secure anymore.
Can you log into the modem and check which Software (firmware) version is listed on the Status page and check on the bandwidth settings as well. If you have V18.104.22.168 loaded, you might want to ask for the trial 22.214.171.124, which resolves issues observed in 126.96.36.199. See the first post in the following thread to ask for 188.8.131.52 from @CommunityHelps:
not sure if this is the screen you wanted? as I was watching it, the signal would flip back and forth from 25 to 50, back to 25, then to 50...
On a wired connection on my desktop Toronto->Telus gave me 491Mbps down and 22Mbps up
My modem is the CGNM-3552 - firmware 184.108.40.206
just grabbed another shot when the signal changed to 50
That second shot is really interesting. If you look at the lower left hand panel, you can see a second unidentified network (orange colour) running in the background when the power level, or perceived power level of your network drops to -50 dBmW. Same channel. That makes me think that you have a guest network running with a suppressed network name, or that possibly, for some reason, a Home Monitoring Network is running from that modem, which would be very unusual. Normally that runs from a Netgear router that Rogers supplies.
Just for trial purposes, can you start the inSSIDer application, and then pull the power plug on the modem. The question of the day is whether or not that second hidden network is transmitting from the modem, or if it actually belongs to someone else. After the modem powers down, you should see your network power level drop on the laptop inSSIDer display and then disappear in about three to four minutes. Then if you have a Netgear router running for the Rogers Home Monitoring, pull the power from that as well and see what happens to that unidentified network.
Let me know what you find.
If that unidentified network stays up and running, then it belongs to someone else who happens to be very close by. That's usually all it takes, is for a close neighbor to bring home a new router or have one installed and your network suffers the consequences. If that is the case, it looks like your going to have to switch to channel 3 and accept the fact that there is overlap with a couple of other networks which isn't as bad as what you have on channel 8. If that is another modem or router that changes channel every so often, that's going to make this situation rather miserable for you. You might want to consider moving up into the 5 Ghz band. From the looks of it, that laptop is single band 2.4 Ghz. Thats why the right hand 5 Ghz display on the bottom is empty.
If that unidentified network dies as well, that means that the modem is transmitting a hidden network for some reason. Home Monitoring comes to mind, which would require tech support to disable if you don't actually have that service running in your home.
I have the guest network turned off, and I don't have home monitoring. The mystery network is me - I noticed it last night so I changed the channel in the router and the channel on the mystery network changed. But I did as you suggested, and that network disappeard along with my named network
I only have the gigabit modem with the built in router, and like I said, the guest network is turned off
Ok, in that case call Tech support and ask the CSR if the Home Monitoring network has accidentally been turned on. That has happened in the past, but we haven't seen it for a while now. Assuming that it has been enabled, ask the CSR to disable it. You should then see the unidentified network disappear from the inSSIDer display and see that your network stabilizes.