For the past couple of weeks, my Internet speed decreases significantly during certain times (usually around 5-10pm, but not always). Pings to google.com can drop from 80ms to 1000ms. I have 3 computers and an Iphone on the network and they are all affected. My ISP informed me that my connection was perfect and that the problem was on my end.

I replaced my cable modem and my router, and this problem still persists. When my connection is slow, connecting my computer directly to my modem (bypassing my router) seems to make my connection return back to its original state. I was thinking this might be my router's problem but I replaced it (and the Ethernet cable connecting my router to my modem) and nothing changed. Can anyone think of a reason why this would happen?

> connecting my computer directly to my modem (bypassing my router) seems to make my connection
> return back to its original state.
I take it that you're using some kind of ADSL over telco lines then?

Does making a normal phone call have the same effect as using a dial-up modem?

Does your cable modem have any kind of setup page?

Open a cmd.exe console, type 'ipconfig'
Then in your browser try connecting to http://192.168.1.1 (or whatever your Default Gateway address happens to be).

For example, I can get a page like this

Pay close attention to things like line rate, noise margins and error rates. Get to know what a "good" page looks like and compare with a "bad" page when things get worse.

Also, do you have a splitter/filter block which splits your telco line into phone and ADSL. Have you replaced that?