Fluctuating router speed

Hi, this is something that has puzzled me for a while. We have a relatively slow broadband speed at around 3.5Mbs however until recently our router has been stable and being "always on" would usually give this consistently. Over the past weeks the speed for no apparent reason drops to around 0.5Mbs requiring a soft re-boot to get the speed back to what it was - this would perhaps happen once or twice a week. It got to the point of annoyance so I changed to the TT supplied router one which although was not as good as the Netgear DGND3300v2 we were using started to act the same after a week or so. I am now onto my third router (Linksys x3500) which ran stable for a couple of weeks then same thing. To my knowledge, interference from nearby wireless has not changed and the router is set to auto channel so that, in theory, it should find the quietest one. I am running a mix of cable and N wireless on the 2.4Ghz channel. I am on TalkTalk and have used their line checker (not sure how good that is) and it says my line is fine and reports no problems.

Any suggestions ?

Does this happe at specific times during the day? Have you got near neighbours who have broadband? If so can you ask them if they suffer in the dame way? Are you using the TalkTalk supplied router? Not much point going to TalkTlk for help, they will likely say it is your BT line who in turn will say that if it is a line fault within the house they will charge for repairs. Have you got a separate ADSL line from the box where the line enters the house? If not have you tried changing the filters?
Sorry for all the questions but down here in Cornwall we had the same problem but now have fibre optic BB. 75mb download all the time!

I'm willing to bet a small amount of money that you do not live in a Market 3 area. (This means Talktalk own your line).

I won't ask where you live, but if you put your phone number/address into here: SamKnows - Broadband Availability Checker see what it says. If you don't see TalkTalk LLU in the list it gives you, then BT own your line.

If this is the case, and this happens at specific times (6pm-12am during the week, all weekend) then the chances are your ISP have not bought enough capacity from BT. When you reset your router, you "jump" to a different server (which may not be so overloaded) and the problem repeats.

Ok, lets establish whether it's you or your line. Please ensure you are using a wired PC to test this.

Hopefully your phone socket looks like this:


If it does, unscrew the faceplate, and you'll find a "hidden" socket. This is the point where your phone line enters your house. Anything beyond this point is not your responsibility, and TalkTalk cannot charge you to fix a problem (if you have one). Plug your router into there (and make sure you use a new ADSL filter if you have one). If the problem does not improve (and I suspect it won't, as you've used 3 routers) then you need to take this up with TalkTalk

Edit: just realised I'm not replying to the OP. On the other hand, this is still good advice so I will leave it up.

Thanks to everyone for taking the time to reply - interesting theories especially the one about the ISP and ownership of the line and possibly restricting bandwidth during peak times if I understood that is where you were coming from ?. I can confirm I have always connected directly to the master socket and have disconnected all bell wires so the speed I am getting is probably best I will can get until such time as fibre comes along but, if you can see cows from your window as we can, chances are it will be take a while... LOL. Also, the DNS server reply looks interesting so I will give that a go. I have not taken a note of when this slowing of the line occurs but now since your replies I will do that and report back.

Again, much appreciate your feedback.