Sync speed dropped after line fault

We had a fault with our phone line on Sunday, broadband kept dropping in and out and phones wouldn't work. BT Engineer came out Monday to fix it, found the fault was a break in the cable from the junction box on the pole outside to where it comes in the house. He replaced the cable with a new one and the phones started working and broadband came back on.

Problem is, my router used to always sync at 8128kbps downstream (max for my 8mb service), never dropped and actual speeds were always great (usually 6mb+, often 7mb+ on speedtests). Now, with the new cable my router is syncing around 7000-7500kbps downstream. My router also reports the max attainable line rate which it used to report at 10000kbps+ and that now only read 7500-8000kbps. Also my actual downstream speed from speedtests is really low around 2-3mb

I contacted Newnet (my ISP) to do a line check and they reported that my IP Profile had dropped to 3000kbps which would explain the low speedtest results. They said it takes 72 hours to sort itself out and that is due on Thurs.

My current router stats are below:

Line Rate: 7360kbps, 448kbps
Attainable Line Rate: 7904kbps, 1108kbps
Noise Margin: 14.7dB, 24.0dB
Line Attenuation: 0.0dB, 5.5dB
Ouput Power: 12.3dBm, 15.8dBm

I know my attenuation can't really be 0.0dB but that is what it has always said even before the cable was replaced. My ISP also got that result when they ran line tests (I do live close to the exchange but not that close!)

Will my sync speed increase back up to the maximum 8128kbps when my IP Profile increases? I know for sure my line should easily support it (it did with the old 20+ year old phone cable before it broke!)

Also, should I keep rebooting my router to try and get my sync speed back up to the max or should I just leave it to sort itself?

Newnet simply need to lower the SNR on your line, this should be a simple request that there technicians can do in seconds if you get to the right person.

Should I wait until my IP Profile changes on Thurs before getting my SNR lowered?

Could you give me a little explanation as to why this may be causing the slower sync so I know what I'm talking about when I ask for the SNR to be lowered?

In reply to a post by Hurders:

Should I wait until my IP Profile changes on Thurs before getting my SNR lowered?

Could you give me a little explanation as to why this may be causing the slower sync so I know what I'm talking about when I ask for the SNR to be lowered?

You were previously achieving the maximum sync speed, probably with an SNR margin of 6dB. BT's DLM line monitoring noticed all the syncs and drops due to the fault and increased the target SNR margin to the maximum, it probably moved in 3dB steps but you didn't notice them with all the disruption.

In theory, once the line is back to stability then the SNR margin should reset automatically after 14 days. However this is not always the case, it may need to be manually reset. If your ISP cannot do it, an email to MrSaffron (Andrew Ferguson, TBB founder) is a way of getting it sorted out.