A week ago, I got FTTC installed to my home in Londonderry (NILDW exchange) with the ISP Goscomb replacing ADSL from TalkTalk née Nildram. Download performance has been very disappointing.
Speeds per second:
Speed checker estimate: 30Mbit / 7Mbit
BT Engineer check: 37Mbit / 8Mbit
Actual speed: 5Mbit / 8Mbit.
I realise that the engineer's check is going to over estimate the speed as there is overhead to take into account (I wasn't supposed to see the result, probably to stop unreasonable expectations). However, my actual download speed is woeful. It does fluctuate quite a bit, I briefly got 34Mbit/s but often get 1Mbit/s - I think 5Mbit is about average.
I have a Belkin N300 router, which replaced a Belkin Pre-N router which had the same poor performance. Plugging the BT modem directly into a PC also gave the same poor performance. I have a PPPoE connection and the MTU set to 1458, as recommended by BT via Goscomb's support.
Goscomb's support, who it has to be said have been very good and helpful apart from the small issue of getting this fixed, are on it. Which is to say, they've asked BT to get on it. A week later and still no improvement - it's a 12 month contract, I wonder if I can get out of it as they're not delivering what they said.