topic Slowness at peak times in Full Fibre

Slowness at peak times

Decing — Tue, 14 Oct 2025 17:03:41 GMT

Hi Everyone,

I'm seeking advice on the download slowness I've been experiencing since last Friday. I am on a Fibre 500 plan, and have FTTP. I would greatly appreciate your thoughts and help on this, please.
Before these issues began, I was generally seeing around 400Mbps on any given day, which I thought was acceptable. Since last Friday, I have been seeing very slow speeds; I am talking sub-1 1Mbps at peak times. I am seeing generally 200Mbps at non-peak times; however, I did check at 2am at night and saw 500Mbps. From 5pm onwards, the broadband is unusable.

Here's what I have tried so far, with little to no effect:
- Removing ONT and Router from the wall for 30 minutes + and going again.
- Factory resetting the ONT and Router.
- Had the ONT replaced by an OpenReach engineer.
- Changed ethernet cables.
- Tested a device directly connected to the ONT.

What other information I have at this stage:
- The speed definitely seems congestion-related based on timings.
- My next-door neighbour with BT as an ISP is receiving his quoted 600/600Mbps
- The OpenReach engineer believes this is not related to OpenReach fixable items.

My belief at the moment is that this is down to congestion/backhaul, but I am being given the run around by TalkTalk support.

Many thanks in advance

Re: Slowness at peak times

KeithFrench — Tue, 14 Oct 2025 21:23:24 GMT

When you tested with a device directly connected to the ONT, what speeds did you get?

Re: Slowness at peak times

Decing — Tue, 14 Oct 2025 21:26:39 GMT

Hi Keith,
Thanks for the message. When connecting directly to the ONT, I had almost identical download speeds, around 3Mbps download.
One thing I have forgotten to mention is that I have noticed that upload speeds seem largely unaffected by whatever is currently going on. I am hitting around 90Mbps upload speed at all times.

Re: Slowness at peak times

KeithFrench — Tue, 14 Oct 2025 21:33:36 GMT

OK, the problem is with the full fibre network then.

The TalkTalk support staff on this forum do not have access to the Full Fibre systems. Therefore, you will need to contact the Full Fibre Helpdesk on: 0345 172 0074.

Their opening hours are Monday-Friday 09:00 to 19:00, Saturday 09:00 to 18:00, Sunday: Closed.

You may not always be able to speak to someone on this number; they may send you a text message instead. If that is the case, the text will contain a link to start an online chat. On that chat, you can insist on speaking to a person, but there may be a delay before you are connected.

Re: Slowness at peak times

Decing — Tue, 14 Oct 2025 21:40:08 GMT

Hi Keith,
The TalkTalk support agents have recommended an OpenReach engineer look at what's going on in the Exchange box. Do you anticipate that this could help this situation?

Re: Slowness at peak times

KeithFrench — Tue, 14 Oct 2025 21:42:00 GMT

Anything on the FF network is a possibility.

Re: Slowness at peak times

Mandisa-TT — Wed, 15 Oct 2025 07:41:31 GMT

Thank you @KeithFrench for your help.

Re: Slowness at peak times

Decing — Sun, 19 Oct 2025 20:53:30 GMT

For this threads reference - The issue was resolved by the OpenReach engineer at the exchange cabinet.
I am now getting consistent download speed throughout the day.

The explanation was:

"They have configured the line from the exchange to your premises and reset the settings to ensure the line is configured and synced with the server".

Unfortunately I don't know quite enough technically to comment on what this means exactly.

Interestingly I also received a TalkTalk email that you would normally see as a new customer "Your line is now online".

Re: Slowness at peak times

mandisa1-TT — Mon, 20 Oct 2025 12:50:18 GMT

Thank you so much for updating us the issue has now been resolved @Decing.