Community Fibre - just installled

I've just had the 500mbps Community Fibre package installed, and while the Linksy app speed test confirms the speed to be 500mbps up and down, my iMac running BigSur is only getting a fraction of this, and they're right next to each other, so I can't imagine what the problem is with the iMac?

Can anyone offer any suggestions?

Edited by MysticLady (Thu 04-Nov-21 18:58:47)

which imac and are you using ethernet or wireless ?

iMac (Retina 5K, 27-inch, 2017) / BigSur 11.6

Connection is via WiFi to a Linksy router.

Can you try using the Ethernet port and re-run the same speed test

Also which linksys router?

It's a Linksy Velop Tri-Band AC2200 / Tri-Band Mesh WiFi Node

Will have a try with an ethernet connection tomorrow. It's awkward as the router is in the next room.

My old BT router sat on my desk, and was always connected via ethernet. This is my first try with a WiFi connection.

Ethernet is even slower (via speedtest.net):

Response time: 2 ms
Down: 88.7
Up: 92.39

I just noticed I set my DNS server to 1.1.1.1, 1.001 some time ago. I can't remember why. Could this be causing it?

Edited by MysticLady (Thu 04-Nov-21 20:30:18)

Linksy app speed test results on iPhone:

Ping: 1 ms
Down: 516 Mbps
Up: 517 Mbps

In reply to a post by MysticLady:

Ethernet is even slower (via speedtest.net):

Response time: 2 ms
Down: 88.7
Up: 92.39

To me that looks like a bad ethernet cable, forcing the link to 100Mbps instead of 1G.

If you open a terminal and type "ifconfig" you should see the speed next to each interface, probably the wireless is en0 and the wired en1.

e.g.

Text
1 23 4	en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 ...        media: autoselect (1000baseT <full-duplex,energy-efficient-ethernet>)         status: active

If it says "100baseTX" instead of "1000baseT" then that's your problem.

As well as a bad cable it could also be a broken RJ45 port in either your Mac or your router, but the cable is the first thing to replace.

In reply to a post by MysticLady:

I just noticed I set my DNS server to 1.1.1.1, 1.001 some time ago. I can't remember why. Could this be causing it?

No.

My money is on the network cable too. Hopefully not a hardware fault with the iMac!

In reply to a post by MysticLady:

iMac (Retina 5K, 27-inch, 2017) / BigSur 11.6

Connection is via WiFi to a Linksy router.

2.4g or 5g connected