Notice the route on Rogers network is different during the slowdown. I believe depending on what route you take out of the Rogers network you get slower performance.
Bad
1 10 ms 9 ms 10 ms 7.11.160.233
2 11 ms 11 ms 19 ms 209.148.242.221
3 11 ms 10 ms 11 ms 24.156.156.173
4 10 ms 11 ms 11 ms pos-0-0-0.gw02.abcgy.phub.net.cable.rogers.com [
24.153.7.118]
Good
1 8 ms 7 ms 8 ms 7.11.160.233
2 11 ms 11 ms 11 ms 209.148.242.221
3 16 ms 13 ms 10 ms 69.63.250.169
4 8 ms 9 ms 9 ms 209.148.224.246
I had this exact issue. I believe it was related to conjestion on Rogers network and or upgrades to their network being performed. It eventually straigtened itself out but it lasted for several weeks. I did contact support on several occasions and first level support seemed to think it was the modem...they said swap for a new one. I never bothered as it has been rock solid since.
For reference my router has always been in bridge mode.
I did experience some packet loss when the issue was occurring. You can do the pings as GDkitty suggested to verify.