New MacBook M1pro using same wired internet as late 2012 iMac - Speeds half that of connection wired to Imac

[El Dubya]

Hi All,
Can anybody shed some light on why my newMacbook M1pro 14 internet speeds are half that of my Late 2012 iMac?
I am unplugging the ethernet cable from the iMac and plugging into the MacBook (using belkin USB ethernet adapter).
Any advice?

 

[Sheepish-Lord]

Is there a setting for it under network preferences? Maybe the speed or duplex settings are incorrect.

 

[darngooddesign]

...(using belkin USB ethernet adapter).

Is it possible that your adapter is restricting the speed?

 

[rmgbenschop]

Which speeds do you get with your iMac and which speeds with your MacBook?

How do you test these speeds?

 

[JPack]

Probably due to lack of updated drivers. A lot of those adapters are based on ASIX chipset and haven't been updated for Catalina or newer.

 

[El Dubya]

Using ookla speediest on iMac and MacBook.
iMac around 350Mbps.
Macbook <150Mbps.
however, when i turn on Wifi and keep the wired ethernet connected to the MacBook through he Belkin adapter i get >300Mbps.
It seems this is the way to go for me for wired.
Odd though.

 

[lcubed]

there's a known issue with the adapters using the older RealTek 8139 chips.
fixed with the newer version of the realtek chip

 

[jav6454]

What is the negotiated speeds? Remember that Ethernet protocol always negotiates speeds with the router/switch.

Also, check your network device to see if there isn't a setting limiting speeds on "guest" devices.

 

[rmgbenschop]

Using ookla speediest on iMac and MacBook.
iMac around 350Mbps.
Macbook <150Mbps.
however, when i turn on Wifi and keep the wired ethernet connected to the MacBook through he Belkin adapter i get >300Mbps.
It seems this is the way to go for me for wired.
Odd though.

I wouldn't use the Ookla Speedtest as it is too spotty with each Speedtest.

Is it possible for you to use iPerf? Get an extra Ethernet cable, plug in your Mac and your MacBook to your router / switch and make your iMac an iPerf server and your MacBook your iPerf client.

And I was making the assumption you are using this Belkin adapter but can you confirm that is the one? This one should have no problem to get near 1Gbits speeds.

 

[jdb8167]

Probably due to lack of updated drivers. A lot of those adapters are based on ASIX chipset and haven't been updated for Catalina or newer.

If you go to Activity Monitor and look for "com.apple.DriverKit.AppleUserECM" and find it then you are using the generic USB driverkit ethernet driver. This quote from the wikipedia article on ethernet over USB explains the problem.

Of these protocols ECM could be classified the simplest—frames are simply sent and received without modification one at a time. This was a satisfactory strategy for USB 1.1 systems (current when the protocol was issued) with 64 byte packets but not for USB 2.0 systems which use 512 byte packets.

A system designed for USB 1.1 isn't likely to perform well on a USB 3/4 system.

Trying to find an ethernet adapter that works with a custom driver is difficult. There is a thread on the subject here on MR.

MacBook Air: USB-C Ethernet unreliable

 

[BanditoB]

You might also want to check whether or not the MacBook Pro has energy savings enabled for the Ethernet adapter. I’m not sure if they will apply to an external adapter, but it’s worth a check.