Dramatic Performance drop - what causes it?

My FTTC connection download speed has dropped from around 63Mbs to about 23 Mbs since last Friday.

WE had a power cut for 45 minutes on Friday evening but my routers were connected to a UPS so should have stayed active.

What causes these drops - the BT Wholesale Performance test tells me that the performance is in the their range of what is acceptable.
This weeks perfomance graph

Why these dramatic drops occur??

Thanks for any info

have you switched it on and off again (the OR modem).

A UPS might be a rather noisy power source, so the sync speed might have dropped due to that - in which case it should come back up.

OK Thanks - how long should it take to get back up to speed?

straight away *if* that was the problem

My speed took a dive recently after a three day cabinet fault, took around 5 days to come back up (from 37-58)

I noticed that your upload speed didn't take a hit until yesterday. I'd leave it a few days and see if things improve, if they don't raise a fault with your ISP, but try a modem reboot first.

Take it you've checked your phone line to see if there is any noise? You can carry out a quiet line test by dialling 17070. and selecting option 2 - it should be silent.

As for BTs acceptable range of performance, well that's just a joke!

Quiet line test was silent

I am talking to the ISP sadly they do not react to the SamKnows figures they need the BT Wholesale test - which confirmed that the speed was significantly reduced.

At least the reduced speed is much faster than it was 12 months ago on regular ADSL

Overnight the performance has gone back to normal

The speed as reported by Sam Knows has now gone back to 61.29 and Jitter levels are now back to .31

Looking back over the Broadband Quality monitor on this site during the period of very slow response the minimum latency graph (the yellow lines) were very prominent (and dominant) they dropped back to a very low figure at midnight last night.

So I do not know what Plusnet or Openreach have done - I would be interested to know.

Edited by DRW (Wed 01-May-13 08:16:25)