Thanks Kitz and Roseway - just for now then, I will put the MTU/RWIN possibilities aside, but it's something to try tweaking in the future. Still monitoring the throughput, but ISP tell me BTw won't act unless throughput is less than 450kbps on an up to 8M service, even when syncing at over 8M and with a profile of 5M+. Crazy!!!
On the other hand, since changing the faceplate (and disconnecting those bell-wires), my connection seems far more stable now at least. I am keen to try and get the IP profile up and then maybe my throughput will go up too.
Prior to replacing the faceplate, my IP profile was down to 3000kbps (12dB SNRM)
Immediately after I replaced it 2 days ago, my sync immediately went up to over 8M (12dB SNR Margin) and the IP profile increased instantly, but only to 5000kbps.
Then I had a single loss of sync yesterday lunchtime and resynced at 6.9M. The SNRM then went up to 15dB. Still I was at 5000kbps profile. I left it at this overnight and my IP profile was still only 5000kbps this morning.
I got tempted this morning and did a resync and got my 8M sync back. (I thought if the differential is at it's highest, then maybe the IP profile might adjust more quickly, but of course, I am causing a loss of resync when I reset so that will go against me).
So now I must wait and hope that within the next 5 days, I can stay at a constant high sync rate will not get any resyncs and that I get a higher profile.
I have some questions that I would appreciate some clarification on:
Why did my IP profile only go up to 5000kbps if my increase in sync speed after changing the faceplate was enough to kick it up immediately, rather than wait 5 days. Shouldn't it have gone up to 7000 kbps in line with the sync?
Immediately on resyncing this morning, my SNRM was still 15dB, but I am getting an 8064kbps sync. Does this mean that my actual target SNR is not set as high as 15dB at the exchange, as I understand that there is a 700kbps loss in potential sync speed for each 3dB the target SNR goes up by? So does this tell me that some of this is just margin on my line?
If I do ever get my profile up to 6000kbps or even 7000kbps (hopefully) by staying at high speed and no loss of sync for 5 days, how do disconnects affect it? How many am I allowed? What if I disconnect my router briefly, several times? Will that just affect the target SNR and not the IP profile so long as my resyncs are all at high speeds? (I understand that if the target SNR goes up then I may get the 700kbps drop per 3dB, but if it is already set to 15dB then it is at it's maximum anyway.)
Many thanks guys - you are being so helpful and Kitz, your site is really informative - thanks again!