Just a reminder to keep it friendly and on topic.
You have a weird way of interpreting things. What is says is that when the guy downgraded he never had the problem on ADSL as did the person moving to Sky. That does not mean the same as it was fibre was causing the problem.
I suppose though going by your interpretation this means that you are contradicting yourself as that would also mean I am not bias towards BT as I am saying the problem is a BT one.
Anyway, as you have said, this is not helping the OP so I see little point in going on with this.
I also have the same problem, I saw many of the FIFA articles from before and didn't want to create an account on here to do a post because I wasn't sure if it would be deleted after BT investigated the issue. After seeing Spluff's article I thought I would register and post as well. I have had the problem since joining Infinity option 2 about two years ago, doesn't matter what time in the day I play I always have stuttering, slow player reactions and running, sometimes freezing which will last about 5 seconds then it will fast forward to catch up with play. The game is unplayable for me on every online game mode and I just don't know what to do. I have moved my xbox downstairs in the liiving room next to the openreach modem and HH3b and connecting via ethernet and it made no difference whatsoever. I have contacted EA many times to be told it is not a problem with them and it is a problem with my ISP. I am not really tech savvy when it comes to these things but have tried everything imaginable including; port forwarding, dmz mode, turning upnp off, wired/wireless, wireless adapters, new homehub 3, reseting my whole xbox and deleting files off there, resetting the HH. I have also cleared my system cache on my xbox and tried playing when nobody else is in the house and of course it made no difference. Like I said it makes no difference what time in the day it is it is unbearable to play. My contract is up in October and I can't wait that long because I have waited long enough.
As Spluff said, I am worried that if I was to move to Sky for example, it may still happen for whatever reason. Also, I enjoy BT Sport and love my football and am grateful for the fact that is free with the broadband. This is has been a terrible experience for me and the amount of white hairs I know have after trying to work out what is wrong is beyond belief! But seriously please someone out there, PLEASE help. I literally only play FIFA really because it's the game I enjoy most (and only game I am good at!) and the fact I can't play on a level playing field is saddening and deeply unfair.
Thanks for reading!
Also it proves that there is a solution out there and that a gamer suffering for 3 years now is happy.
Would love to know what causes this problem and why changing ISP has fixed it for this guy.
You need to see what is happening your end by looking at the TCP traffic.
One of the things that could be tried is to put you on 'Elevated Best Efforts'. This would give your traffic a preferential weighting in the 21CN network. It would be a very simple thing to do and try to see if that makes any impact. Again, you might struggle to get BT Retail to do this for you - but they have nothing to lose to try it for you (cost is £3 per month normally).
There are going to be some changes to FTTC coming up. One of the things will be new DLM Profiles which better suit the end users and their needs. Each ISP has been invited to put forward what they want, but I understand that two types of profiles (for gamers and IPTV users) are popular requests. I think it will be a number of months before this is introduced, but this may resolve things for you.