Weirdly slow download speed

I've just been on the phone to Zen support because speedtest.net says my upload speed is 20MBps and the download speed however starts out about 50Mbps and scales down during the test to about 20Mbps. Nothing tried during the call, router resets, connecting directly to the Fritz box with ethernet cable whilst disabling the Wifi, etc. changed this performance.

They says Openreach tested my line and got 80/20 speeds. They're sending out a new router but it seems to me a bit unlikely this is caused by the router. They insisted there was nothing more they could do though.

Websites do seem to load slowly, and what's really weird is that some other speed tests are even worse; the Fritz one itself and the think broadband test report speeds of more like 2-5Mbps download.

Anyone know why this might be happening? Is it more likely to be a temporary provider issue or could it really be my Fritzbox router?

I just noticed I linked a previous result from 2019 in my sig. Here's the previous result:

https://www.speedtest.net/result/8718060020.png

And here's what I got from running it just now:

https://www.speedtest.net/result/18636771728.png

If you are using a Mac with TAHOE installed WIFI can be a disaster. Lots on Google about it .
A quick workaround is to "forget this network" and then reconnect which works sometimes.

Got the same issue on FTTP. Started in the early hours of Saturday morning on 20th Dec at around 0:30. Reported to Zen but so far got nowhere. Can see packet loss of between 3% and 11%. Latency has increased a little also. If I try running a PPPoE connection direct via the ONT I get the same speed issues meaning the problem lies outside of anything local to my network/router.

Symptoms show as download speeds of around 3mbps to Zen’s own Speedtest server. Other Speedtest locations are a bit better, just seems random what is and isn’t impacted. There’s just random problems with lots of websites and downloads generally. Upload is perfectly fine. If I manage to VPN out to certain destinations, the speed is better which suggests something is broken in Zen’s network. They’ve had me factory reset the ONT but didn’t fix the problem. Hoping to get further on Monday when they open.

So today my down speed is back to about 72MBps, showing that it very likely wasn't my router at fault and it was Zen's network, something the support team member I was talking to insisted it wasn't.

Zen really aren't what they used to be.

Sounds about right.

I had packet loss on my line switching from Yayzi to Zen. Zen denied any issues on their side and blamed City Fibre.

Yayzi was a City Fibre connection also.

Glad its all working again

You need to fix "Gbps" in your signature btw

Did i stutter? gigaper bits second.



Thanks. Thats been like that for ages! I need to update it all anway

Edited by Seansmit17 (Tue 30-Dec-25 02:54:07)

Fixed

Connection Speed: DL: 2.5Gbps UL: 2.5Gbps
Speed test: DL 2.2Gbps UL: 2.3Gbps
Connexin
https://www.speedtest.net/result/18655446452
Router: GL-iNet GL-MT6000

Edited by Seansmit17 (Tue 30-Dec-25 02:55:19)

In reply to a post by Seansmit17:

Did i stutter?

Hehe