nbaset - Jiri Brejcha

OWC Thunderbolt 3 to 10 Gbps Ethernet Adapter – The Fastest Multigigabit Adapter For Your Mac

When it comes to the fastest copper Ethernet adapter for your Mac, you have only 2 options:

If your other half approves, get yourself an M1 Mac Mini with built-in 10 GbE port. It doesn’t get much better than this.
Or you can consider an add-on 10 Gigabit Ethernet Thunderbolt 3 adapter for your current Mac.

We will focus on the latter today.

Thunderbolt 3, not USB

While the USB-C connector might temp you to connect these adapters to a standard USB port, these adapters don’t support USB protocol. They use Thunderbolt 3 and they happen to use the same USB-C connector as USB. That’s the only thing USB and Thunderbolt have in common. Before you order one of these adapters, double-check that your computer supports Thunderbolt 3. That should be most new MacBooks, Mac Minis, Intel NUCs and similar platforms.

Which 10 GbE adapter shall I buy?

I tested two of these Thunderbolt 10 GbE adapters. One made by Sabrent, and the other by OWC. They both look alike, both perform very well, both get quite warm, and both work out of the box on macOS. Yes, no driver installation required on your part on macOS! 🎉

Mainly because of the loose Sabrent cable issue explained below, I recommend the OWC adapter. It comes with great documentation, and even the Thunderbolt cable itself is thicker, feels premium, and most likely delivers better shielding.

OWC Thunderbolt 3 10G Ethernet Adapter OWCTB3ADP10GBE

From throughput perspective, I personally tested it up to 3 Gbps down and 3.3 Gbps up using iperf3 with default settings. The limitation is on my part, I just don’t have another 10 GbE computer I could test against.

I’ve seen reports of:

between 7 Gbps and 8.74 Gbps uplink speeds with default iperf3 settings
9.5 Gbps uplink iperf3 speeds with Jumbo frames enabled

When I reviewed 2.5 GbE and 5 GbE adapters, this setup has become my reference I ran all iperf3 tests against.

It supports Jumbo frames including a custom MTU setting

VLAN tagging

The OWC adapter also supports VLAN tagging. Here is my Trunk port with Native VLAN 129:

Trunk port configured on the access switch

Let’s tag all traffic with VLAN 130:

Verify that we are indeed in VLAN 130:

VLAN 130 is being used instead of the Native VLAN 129

If you only want to use VLAN 130 (without touching the Native VLAN 129), you can disable the adapter itself. VLAN 130 virtual interface will stay up and forward traffic.

Disable the Native VLAN 129 and only use VLAN 130 for all traffic

Sabrent Thunderbolt 3 to 10 Gbps Ethernet Adapter TH-S3EA

I won’t go into the detail, but my main challenge with the Sabrent adapter was its loose Thunderbolt cable. The connection between the USB-C socket on the adapter and the USB-C connector on the Thunderbolt cable is very loose and practically pulls out just by the tension of the cable itself. It might have been just my unit, but I can’t recommend it.

Sabrent Thunderbolt 3 to 10Gbps Ethernet Adapter on the left

It almost felt like it needed some hot glue to keep the Thunderbolt cable connected

What about Windows and Linux support?

I tested the Sabrent adapter on Windows 10. It required a Sabrent driver installation and then it worked just fine. I would assume the same for the OWC.

I don’t have a Linux computer with a Thunderbolt port, so I can’t share anything on that front.

Sabrent 5 GbE Multigigabit Ethernet Adapter

Sabrent NT-SS5G is a 5 GbE USB adapter, which allows you to achieve higher throughput than 2.5 GbE adapters, and break the 2.35 Gbps barrier. It works great on Windows. If you are a macOS or Linux user, I recommend you consider other options like this instead.

The adapter itself is larger than 2.5 GbE adapters, it uses AQC111U chip, and ships with short 2 detachable USB-A and USB-C cables. USB-C port on its back connects the adapter to your computer. A metal shell protects it, serves as a heatsink, and also adds to its weight.

Windows 11

Install the driver from Sabrent’s website and you are good to go. In my tests with this Topton M6 Mini PC, I measured 2.93 Gbps down and 3.44 Gbps up with default iperf3 settings.

2.93 Gbps down and 3.44 Gbps up with default iperf3 settings

In adapter options, you can actually configure quite a few things including Jumbo frame support. Note that these are fixed values.

macOS

I can’t recommend this adapter for macOS users. It forces you to disable macOS System Integrity Protection (csrutil), otherwise it won’t work. It might be okay for a proof of concept or lab setup, but I would hesitate from using it in production.

This is how to install the driver if you were interested:

Install the driver using the pkg file provided by Sabrent. It installs a Kernel Extension (kext), which drives this adapter.
Enable the extension by going to System Preferences > Security & Privacy > enable the extension > Reboot.
After reboot, unplug the adapter and plug it back in.
It should work as long as you leave the System Integrity Protection disabled.

From throughput perspective, it saw download speeds of 3.30 Gbps, and upload of 3.45 Gbps. This was with default iperf3 settings, standard 1500-byte MTU and one stream. Great results considering that this adapter’s USB interface maximum theoretical throughput is 5 Gbps.

In my view, you might be better off buying a 2.5 GbE adapter, which can push 2.35 Gbps up and down consistently and with no driver installation needed. I tested one here. Alternatively, a 10GbE Thunderbolt Ethernet adapter is even faster choice, but more costly, and larger form factor. Or, if your other half approves, treat yourself to an M1 Mac Mini with built-in 10 GbE 😉

Linux

I tested this adapter on 64-bit Raspberry Pi OS running on Raspberry Pi 4. Although the default driver distributed in Linux Kernel 5.15 works, it doesn’t even deliver symmetric 1 Gbps.

Let’s download the latest driver from Sabrent’s website. Unfortunately that doesn’t seem to be able to compile for 64-bit OS. I tried compiling on 32-bit Raspberry OS, to no avail. If you have any ideas, please do let me know.

So, on Linux, a Realtek RTL8156B based 2.5 GbE adapter might be a better choice for you. Here is the one I tested.

Plugable 2.5 Gigabit Ethernet to USB 3.0 Multigigabit Adapter

Plugable makes this inexpensive 2.5 Gigabit Ethernet USBC-E2500 adapter. It is based on Realtek RTL8156B chip. On Windows and macOS it works out of the box. If you want to use it on a Linux machine like WLAN Pi Pro or Raspberry Pi 4, expect some troubles along the way, but good performance when you get there.

The USB-C to USB-A adapter is allows you to use it with a MacBook (USB-C) or Raspberry Pi 4 (USB-A)

The adapter itself has a plastic shell and is very lightweight

Windows 11

When they say “update the driver using Windows Update first”, they mean it. Windows 11 will recognise the adapter and you can start using it, but the default driver distributed with Windows 11 significantly reduces this adapter’s performance.

727 Mbps down and 2.34 Gbps up with default driver

Now, let’s use Windows Update to download the latest driver.

Don’t forget to update the driver using Windows Update

As you can see, download throughput (from iperf3 server to iperf3 client) has dramatically improved.

1.78 Gbps down and 2.35 Gbps up with updated driver

Although the box suggests Jumbo frame support, Windows driver settings don’t give me any option to edit the MTU size. So, I assume Jumbo frames are not supported.

MacOS Monterey

On macOS, this adapter works out of the box with no additional driver installation required. That’s a very nice surprise. And performance is great.

Auto-negotiation worked just fine. If you want to configure speed or MTU manually, you can, but Jumbo frames are not supported on macOS either.

Linux

Now the bad news. If you are considering to use this adapter on a Linux machine, the default driver cdc_ncm is a trouble as it only supports 2.5 Gbps Half duplex. Setting Full duplex manually using ethtool command doesn’t work either.

Default driver only supports Half duplex

As you might expect, with the default driver and Half duplex, throughput is very poor.

1.22 Gbps down and 704 Mbps up with the default cdc_ncm driver on WLAN Pi Pro

On WLAN Pi Pro and Raspberry Pi 4 running 5.15 Linux Kernel I managed to fix the duplex issue by the steps listed below. But I hit new auto-negotiation issue between the Plugable adapter and Cisco Catalyst WS-C3560CX-8XPD switch. It took the adapter to eventually negotiate 2.5 Gbps Full duplex around 15 minutes of constantly flapping the interface. Forcing speed and duplex on the Plugable adapter by ethtool did not work. Certainly not ideal, and definitely worth testing before you commit to the Plugable adapter. With other multigigabit adapters, the Plugable had no negotiation issues.

1.7 Gbps down and 2.09 Gbps up with r8156 driver on WLAN Pi Pro

1.91 Gbps down and 2.06 Gbps up on Raspberry Pi 4 using the correct r8156 driver

Raspberry Pi 4 also known as WLAN Pi Community Edition

How to force Linux to use the right driver

To enable Full duplex capability, we need to tell Linux to use Realtek r8156 driver instead of the default cdc-ncm.

Download the latest driver from Realtek’s website
Unzip it and copy the 50-usb-realtek-net.rules file to your Linux machine
On the Linux machine copy this file here sudo cp 50-usb-realtek-net.rules /etc/udev/rules.d/
Reboot by sudo reboot
Verify that the adapter negotiated 2.5 Gbps Full duplex and is using the Realtek r8156 driver.

Multigigabit Ethernet on the Raspberry Pi 4

Update: The Linux driver for this adapter does not seem to perform great. I tested a 2.5 GbE adapter based on Realtek chipset, which might work better for you. Here is my review.

I also tested this adapter on Windows 11 and macOS here.

With the first consumer Wi-Fi 6E routers already shipping, and enterprise access points being worked on, I think it is now time to up my iperf3 game. While the standard 1 Gbps adapters push around 950 Mbps of TCP traffic, the iperf3 server will sooner or later become a bottleneck for throughput measurements.

Raspberry Pi 4 (RPi4) is widely available, and there is a chance that you might already own one. So, the question is, can it support multigigabit speeds?

Although it does not have any PCI Express slot available, it does have a couple of USB 3.0 ports. I researched USB 3.0 multigigabit NBASE-T Ethernet adapters, and purchased a few. At the time of writing, Linux kernel 5.10 is the Raspberry Pi OS gold standard, and that’s what I used for all tests.

TL;DR … give me the short answer

The maximum TCP throughput Raspberry Pi 4 iperf3 server can handle with a 5 Gbps USB 3.0 Ethernet adapter. These were 90-second iperf3 tests with standard 1500-byte MTU and a single iperf3 stream.

Download (from RPi4 server to a client): 2.05 Gbps
Upload (from a client to RPi4 server): 528 Mbps

If you can enable 9000-byte Jumbo frames on all devices involved in the data path, the upload speed becomes much healthier.

Download (from RPi4 server to a client): 2.05 Gbps
Upload (from a client to RPi4 server): 1.73 Gbps

USB multigigabit adapters

There are a few available on the market. After reading a dozen of reviews, I decided to get 3 adapters from a company called Sabrent. They make adapters with nice metal cases, which helps with dealing with the heat they dissipate.

Left to right: 2.5 GE USB 3.0 Sabrent NT-S25G, 5 GE USB 3.1 Sabrent NT-SS5G, 10 GE Thunderbolt 3 Sabrent TH-S3EA

The 5 GE USB 3.1 Sabrent NT-SS5G is the only I recommend for use with the RPi4:

It uses the Marvell Aquantia AQC111U chipset
It works out of the box with Raspberry Pi OS and
It works on Windows 10 after you install the driver
It ships with USB-C and USB-A cables so you can connect it to your laptop using USB-C or RPi4 using USB-A
Unlike other brands it does not overhead or disconnect due to instability

5 GE USB 3.1 Sabrent NT-SS5G ships with both USB-A and USB-C cables

ServeTheHome team did a great job of comparing the 5 GE adapters using the same chipset as the 5 GE USB 3.1 Sabrent NT-SS5G. It came out as a clear winner:

USB 3.1 Gen1 To 5GbE Comparison Table AQC111U Based Q1 2021 — Credit and kudos to ServeTheHome

Why not use the cheaper 2.5 GE USB 3.0 Sabrent NT-S25G? Because it uses Realtek 8156 chipset, and there is no suitable Linux driver available at the time of writing.

Why not the 10 GE Thunderbolt 3 Sabrent TH-S3EA? Although it has a USB-C connector, it is not a USB adapter. It uses Thunderbolt 3 protocol, which is not supported by the RPi4.

Test setup

I use RPi4 with PoE HAT, because it has a fan on it, and I power the unit by a USB-C charger. Both multigigabit adapters involved in the test are 5-Gigabit Ethernet capable Sabrent NT-SS5G. The best part is that these work out of the box on the Raspberry Pi OS with no action required on your part.

But, if you are considering the purchase of these adapters for your Mac, please stop. After you plug the adapter in, it uses Apple’s 1 Gigabit Ethernet adapter driver, and it would only auto-negotiate 1 Gbps. To enable 2.5 and 5 Gigabit speeds, and support for Jumbo frames on Mac, you have to disable Apple System Integrity Protection (SIP) tool, and install a legacy kext Sabrent driver. I would discourage you from making these security compromises. If you are interested in a multigigabit adapter that works with macOS out of the box, tune in later and read this review (link to be added).

How to increase the MTU and enable Jumbo frames?

On the Raspberry Pi:

sudo ip link set dev eth1 mtu 9000

On the Cisco Catalyst switch running IOS:

System Preferences > Network > Adapter settings > Hardware > MTU on macOS

Conclusion

The RPi4 allows you to test download-only throughput up to 2 Gbps with standard MTU. Upload speeds are really poor and you would be better off using the built-in 1 Gibabit Ethernet adapter. You can use the RPi4 to run a few other tools, scripts, or take wall attenuation measurements.

With Jumbo frames enabled, 2 Gbps/1.7 Gbps is good enough for lab use or demonstrations. Keep in mind that you would have to enable Jumbo frames on all devices (RPi4, MacBook and the switch in my case).

The main cause of the relatively low performance is the storm of IRQ hammering the RPi4 CPU:

In a computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Hardware interrupts are used to handle events such as receiving data from a modem or network card, key presses, or mouse movements.
Source: Wikipedia.org

If your use case requires a powerful iperf3 server, Apple’s Mac Mini with built-in 10 Gigabit Ethernet adapter would be something to consider today. It won’t be the cheapest option, but you won’t have to worry about performance or USB dongles. From what I’ve found, it uses Marvell AQC 1113 chipset and does 9.4 Gbps with 4 parallel iperf3 streams.

Disclosure

I purchased these adapters myself. No one asked me, or paid me, to write this blog post. I was as curious as you to see how the RPi4 performs when it comes to multigigabit Ethernet.