Broadband speed - At the end of my tether...

[#1]

Way back when PlusNet introduced 8 meg broadband I was very happy.
Unfortunately my line was only capable of 6 meg but that was plenty for me.
Then there were the infamous speed problems that most people experienced.
Since then things improved for a while but in the last year my speed has steadily dropped.
For the past few months my speed has gone down to around 3 meg, not great but still usable.
After talking with a neighbour, who is with another provider, I discovered she has enjoyed around 8 meg broadband for well over a year and has never experienced any speed issues whatsoever.
Now she is the same distance from the exchange as me (which I had always assumed was one of the problems).
For the past 4 days my speeds have been unbearable, little better than dial-up and copmpletely unacceptable.
As my neighbour is enjoying high speeds I figured there must be something wrong somewhere.
So in the past couple of days I have replaced my router, all the cables and microfilters but it has made no difference whatsoever.
So next I tried disconnecting the sky and telephone lines leaving only the router connected, in case of interference.  Again, not even a slight improvement.
So then I tried connecting directly to the test socket (generally I have to use one extension because the master socket is too far away).
Again, no improvement at all.
I have done all the diagnostics and speed tests and there appears to be no problems with the line or the exchange.
So something is going on here and I'm not over my download limit either.
So what other reasons could explain these gradually deteriorating speeds?
Although I say my speeds have gradually dwindled, I mean generally, on average.  The actual speeds during that time have been erratic to say the least.
So is this down to PlusNet?  If not, why is my neighbour enjoying such excellent speeds with another provider?
If this isn't resolved very soon (whatever the cause might be) I will be moving to another provider just to see if there is any improvement.  If not, I've lost nothing, I'm no worse off than I am now.
As far as I'm concerned it's unacceptable and I'm not prepared to put up with it any longer.

[#2]

When you made your changes, were you checking your sync rate, or your download speed?
If you were doing speed tests, then these won't be representative of your actual connection speed.
What you need to do is completely eliminate all internal wiring by plugging your router into the master socket.  When you have done this, you need to look at the router configuration and see what the Sync speed is reporting.
Also, it may be worth running a BT speedtester at http://speedtester.bt.com and seeing what your IP profile is set to.
Try those, and report back
B.

[#3]

You definitely need to do that to get some basic facts.
I'm currently helping out a friend who gets about 2Mb from his "8Mb" broadband, while his neighbours either side get 5Mb and 6Mb; all confirmed via the BT database.
I'm working through things with him, but it's a combination of all sorts of things, including wiring, Sky boxes, router firmware, MTU/RWIN etc. etc. Tomorrow he should get a new Master socket with filtered faceplate and we'll be working forwards from there! 
Finally, just one thing to check - what Plusnet package are you on and where are you in relation to your quota?

[#4]

Quote from: Barry

When you made your changes, were you checking your sync rate, or your download speed? If you were doing speed tests, then these won't be representative of your actual connection speed.

The reason for this is that if you are having problems with your connection, BT will set your IP Profile down to a much lower speed. Only after you have had a solid sync at a higher speed for a few days will BT put your IP Profile speed back up. Only after that happens will you see improved results of speed tests.

[#5]

@juliapeez

Quote from: juliapeez

For the past 4 days my speeds have been unbearable, little better than dial-up and copmpletely unacceptable.

Just to reiterate a point made by HPsauce, this may indicate that you've gone over your usage allowance for this billing period and that your speed has been restricted.
What product are you on and what's your current usage?  Are you on an old product - Premier Option 1, perhaps?

That product will throttle your speeds on a gradual basis dependent on your usage - first down to 2Mbps when you go over 13GB and then down to 1Mbps at 17GB. See here.
If you're on one of the new BBYW products then, unless you've ticked the PAYG option on this page, you'll be rate limited to 128kbps if you go over your included allowance.
I'd check this out first before going down the route of problems with the line. 
If it turns out to be usage restrictions and you're on a legacy product (Premier etc.), dependent upon your usage pattern it may be worthwhile considering a move to the newer products.  If you're already on one of the BBYW products, you could tick the PAYG box or add extra usage up front.

Edit: Scrub that! I didn't notice this

Quote from: juliepeez

I'm not over my download limit either

but have just re-read your post!

[#6]

Hi Julie,
I've tried running some tests on your line but unfortunately haven't been able to do so as you don't appear to be connected to the internet.
Could you possibly reconnect and let me know when you have done so?