Bad Wi-Fi Signal - iMac M1

[Oliver G]

I just upgraded to an iMac M1 from a 2017 4K iMac and have been having some trouble with the Wi-Fi. Side by side in the same room I'm getting around 50mbps on the 2017 4K iMac but barley hitting 15mbps on the M1 iMac.

Here are the stats from both machines with the 2017 4K iMac on the left and the M1 on the right.

I know the M1 iMac supports Wi-Fi 6 and I've ordered a Wi-Fi 6 modem but that won't get here for a few days but is there anything else I can do to improve the speed while I wait. Ethernet is not an option unfortunately.

 

[meson]

Given that your Tx Rate is well under 300 Mb/s, it is telling you that the signal strength is a bit weak at your location.

The RSSI value of -70 dBm indicates a decent, but not great connection for both iMacs.

The Noise of -78 dBm and -76 dBm indicate that the M1 is experiencing a bit more background noise in a pretty noisy environment (I usually see numbers in the -90's for the background noise) and that may be enough to drop off the speed a bit and cause issues.

It appears that Optus_1C4C8E_2GEXT94, which is likely the 2.4 GHz network on your router (and possibly coming from a wifi extender access point given the name) may have a little better signal strength, and may offer improved performance. Try connecting to that network. Being the 2.4 GHz band, it will have a little better range than the 5.0 GHz band. I'm assuming that you are fairly far from the router and/or receiving the signal after passing through walls and/or floors.

Additionally, try powering off the 2017 iMac and see if reducing the number of active devices in the room has an effect. By having both side by side, you may have interference problems between them. I'm not sure which side the WiFi antenna is on, but swapping the place of the machines may improve or hurt things as well.

 

[Pressure]

You are most likely experiencing interference. Remember that all devices transmitting on 2.4GHz are fighting for the same available bandwidth from channel 1 to 11.

5GHz have far more channels available and less interference at the cost of lesser coverage.

Every device connected on 2.4GHz are also sharing the available bandwidth from your router.

 

[Oliver G]

Given that your Tx Rate is well under 300 Mb/s, it is telling you that the signal strength is a bit weak at your location.

The RSSI value of -70 dBm indicates a decent, but not great connection for both iMacs.

The Noise of -78 dBm and -76 dBm indicate that the M1 is experiencing a bit more background noise in a pretty noisy environment (I usually see numbers in the -90's for the background noise) and that may be enough to drop off the speed a bit and cause issues.

It appears that Optus_1C4C8E_2GEXT94, which is likely the 2.4 GHz network on your router (and possibly coming from a wifi extender access point given the name) may have a little better signal strength, and may offer improved performance. Try connecting to that network. Being the 2.4 GHz band, it will have a little better range than the 5.0 GHz band. I'm assuming that you are fairly far from the router and/or receiving the signal after passing through walls and/or floors.

Additionally, try powering off the 2017 iMac and see if reducing the number of active devices in the room has an effect. By having both side by side, you may have interference problems between them. I'm not sure which side the WiFi antenna is on, but swapping the place of the machines may improve or hurt things as well.

Thanks for responding, I've powered off the 2017 iMac as I only had it on to grab those stats. The Tx rate has improved a bit to 90-120mb/s but I'm still only getting 15-20mb/s on Speedtest.

The modem is located at one end of the hallway and the iMac is in a room at the other end so approximately 10 metres away.

It's really quite strange as I've been getting a solid 40-50mb/s for months now and the only change has been the iMac M1.

I've been planning for a while to introduce a Wi-Fi mesh system but I'll wait until I get my Wi-Fi 6 modem.

 

[meson]

Just a couple more questions.

Did the reduced download rate start after a software update?

The reason I ask is that back in August after performing a simple MacOS update (11.3 -> 11.4 or 11.4 -> 11.5), I completely lost the ability to connect to WiFi. I tried everything I could find to try and nothing worked. I reinstalled MacOS on top of my current installation, and nothing. The only that worked was a complete wipe and install from scratch. That said, this was my work machine, which means that although I have admin privileges, I am still hampered a bit by their Jamf profiles.

As much of an inconvenience that it can be, it may be where you end up.

Are you using a modem and router supplied by your internet provider?

They tend to offer wireless routers that seriously underperform. I would recommend providing your own equipment than using theirs. At the end of the day, I think your issues are caused more by the signal to noise ratio than anything.

Hopefully your new hardware provides a strong enough signal to remedy the situation.