Sync Speed suddenly dropped

[#1]

The sync speed on my modem has suddenly dropped from 5500 to 3232 with a subsequent drop in bandwidth i haven't changed any thing on my system any ideas as to why the sudden decrease in line speed?
Thanks

[#2]

Currents DSL stats

[#3]

Hiya,
Do those line stats change at all if you reboot your router?

[#4]

Hi James, yes the noise margin can move quite a bit as well as the sync speed depending on what time of day I reboot. 7db is the lowest the noise margin it has been though, last week it was around 12-15db. The sync speed is currently 3168 with a noise margin of 7db.
Thanks

[#5]

the best time to reboot is after daybrak and definitrly before 16:00,  The worst from about 14:00 up to half past midnight

[#6]

Will try again tomorrow morning and note the line stats, I am a bit worried in case there is some problem with the line as I used to get throughput approaching 5500kbit/s where as now i am lucky to achieve 2700kbit/s.
Ta

[#7]

Just rebooted the router, line stats attached. Just run the speedtest and am getting 2397kbps down speed, where as last week i was getting 4773kbps.
Thanks

[#8]

Thanks - Do you know what the noise margin was showing as beforehand?
Have you made any wiring changes at all recently?  The line looks normal, but it's definitely synchronising at a lower speed than I would have expected for that length of line.

[#9]

Hi James, last week the down link noise margin was around the 10-15db mark.
No have not made any changes in the past month.
Thanks

[#10]

Right - That's interesting.  Normally a decrease in noise margin results in an increase in sync speed, becuase BT force the sync speeds as high as it will go until they hit 6dB.
However, I've seen the odd case where a high noise margin (because it means there are less errors present) actually causes an improved sync speed.
If you like, I can ask BT to force it to 9dB and see if that makes any improvement?

[#11]

Hi James, yes that was my understanding that a decrease in noise margin would result in a increase in line speed. Yes if you could ask BT to force it to 9db, I am at work at the moment, how long do these things take?
Thanks

[#12]

It generally varies.
I'll get a fault raised on your account and we'll see where we go from there.

[#13]

Ah, minor problem.
Can you power up your router for me when you get back in please?  I need to run some checks from this end first before I can get anything raised.  I'll need you to keep it turned on too.

[#14]

Interleaving, when was this switched on by BT?

[#15]

That won't account for a 2Mbps sync drop.