I've done a few speedtests since mine was fixed 2 months ago, and I've never seen any single thread issues since then.

In reply to a post by Deft:

I've done a few speedtests since mine was fixed 2 months ago, and I've never seen any single thread issues since then.

Thanks for the reply.

How long did you have problems for before Zen fixed it?

Got a wee bit extra speed today, a whole 1.5Mbps.

Will give it till my next billing date and if not any better will start looking for another ISP.

Well it was one of these threads here that alerted me to the issue. You could argue that perhaps I wouldn't have known otherwise, as mostly nowadays providing Netflix and Amazon stream video ok I don't get too twitchy on speed requirements (I sync at around 40/10 FTTC).
I logged a support ticket in June which acknowledged the issue and asked me to try doing direct tests off the Openreach modem too. My setup makes this a bit awkward and it wasn't causing me enough issues to pursue the matter vigorously. I did keep adding the odd speedtest on Zen's version of the Thinkbroadband tester just so they had some more data.
Then I saw this post and it seemed like Zen had found some kind of fix / workaround - PM'ed my Zen username to jongreen further up and it was fixed. No problems since.

I've just replaced my Billion 7800N ADSL router (using the HG612 modem and WAN interface on the Billion) with a Ubiquity ER-X router and re-run the speed test.

It's had a marked change on my single thread download which now maxes out at virtually the same speed as the x6 test. I wonder if there's a limit (unintentional I would assume) within the Billion and how much it can download per thread.

Test Results

Second Test

Edited by bsdnazz (Fri 20-Jan-17 11:53:31)

After a couple of months of normal service the slow single speed has returned for me.

Anyone else having the same problem?

Earlier Tonight

Just Now

Not only that but I have lost about another 8Mbps of speed and am now synced around the 58Mbps. So in two years I have lost about 20Mbps in speed from the days of 79.9Mbps.

I'm with IDNet and recently I have been experiencing the same problem. IDNet say they can't see any problem at their end but clearly something is amiss. Are you on Zen or BT backhaul?

Well I was on BT Backhaul.

But, looking in my Portal on Zen I have just seen I have had a "Zen Fibre Migration GEA- Fulfilled on the 08/03/2017", which I take it to mean I am on their backhaul some of the way now, with the closes POP being Stirling, I think.

Coincidently, this is about the same time as my connection started playing up, download speed dropped, slow single thread speed , downstream Interleaving being turned off and G.INP being turned off, but apart from that everything else is the OK.

Interesting.

I assume I am on BT backhaul, though I believe IDNet do make some use of Zen. IDNet support only ever refer to "our supplier" so I have no way of finding out if Zen is involved.

I would think if IDNet are buying in services from Zen, then it would be their LLU services.

It's difficult to see what IDNet would think there was any value add in terms of buying in BTW services from Zen rather than buying them directly.

Just my 1p's worth.

In reply to a post by Scottish_Pete:

But, looking in my Portal on Zen I have just seen I have had a "Zen Fibre Migration GEA- Fulfilled on the 08/03/2017", which I take it to mean I am on their backhaul some of the way now, with the closes POP being Stirling, I think.

You've moved to Zen's network, which means there is no BT Wholesale in use any more for your connection - it's Zen backhaul all the way from the Openreach handover point to Zen's core. The fibres in your area probably go back to a larger exchange where Zen has presence, which could be many miles away. jongreen from Zen tell me that the fibres from my area go back to an exchange nearly fifteen miles away where Zen has presence.

You'll now be on a different VLAN over the Openreach infrastructure. This change of VLAN might have caused a DLM reset, hence your loss of G.INP and all the consequential issues. If you leave things alone, hopefully G.INP will be put back on your downstream and everything else goes back to what it was.

If you have single thread performance issues once things have settled, send a private message to jongreen so that he can investigate if it's the known backhaul configuration issue.