The changing filters etc is the usual excuse that any ISP may quote you do, and occasionaly that IS the cause. Seriously!
I had one filter in for years, and swapped it with the shiny bonding routers filters. Speeds were 'ok' at the start, and eventually went doen hill. *I didn't need to blinking change cables etc, I know
what I'm doing, and done it a million times for flips sake. I am not StuPid
The very friendly Be* guy asked me IF I would just give it a go to see what happened. I eventually went over and changed it. and I thought, is there any other excuses to hit me with? Never mind.
So I logged back into my BeBox and the speeds were back up to 18meg down, and 1.4meg up. WRONG thinks me, it should be my BETTER DGN2000 that gets the speeds up to that speed? - WAHOO!! Going to wire it up tomorrow to see if it goes up higher before any tweaks. Will just see how it runs with the Netgear for a while, and at least the BeBox can be >dare-say-it< RELIED UPON!
If in doubt mate, try everything - just do it one simple bit at a time. Take your time with it, and it's done right.
Asking here is always wise too. You always get knowledgable people in here who are always willing to help when they can.
Another tip: Make sure that every phone socket in your house has a filter on it.