I have now, for the past 2 months had a recurring issue on my fibre connection with my ISP. On many (not all) evening and at indeterminate times my speed drops from cap at my synch rate down to around the 1-3mb/s mark. It happens almost instantly and when it recovers I am back at full speed a few hours later. Prior to the issues which have effected my IP profile I had constan speeds of ~70mb/s.
What is particularly strange - for example as can be seen here http://www.speedtest.net/my-result/5654044822 my upload is never affected. The download is also odd in so much as througput the first few seconds of the test drops down from 50-2mb/s whilst been very 'janky' like data is coming in fits and spurts.
I have submitted a number of Tap reports and been told the issue is resolved previously. It has also been blamed on congestion too. I have tried ruling out my router by connecting my PC direct PPOE to the fibre router.
Unfortunately I am in contract so have no room to move. I have logged a complaint now too. I have used them for a long time now with no issues which is why I have been loath to name but I am interested if anyone else has seen this issue and has any idea what might be causing the strange download speed and if I have any recourse?