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Fun With Multigig Ethernet

June 11, 2022

I love the new batch of multigig Ethernet peripherals that allow you to run 2.5 Gbps and 5 Gbps over your existing Cat5e cabling.

Comcast’s modem supports 2.5 Gbps, and I can now tap into the full 1.4 Gbps download capacity over wired Ethernet.

But not all multigig Ethernet devices are created equal!

Switches

From my experiments, the best option for switches appears to be the 10/5/2.5 Gbps ones that give you 10 Gbps bandwidth between local devices, and 5 Gbps between switches over Cat5e. I’ve had a really good experience with the TRENDnet TEG-S750.

https://www.trendnet.com/products/10g-switch/5-port-10g-switch-TEG-S750-v1

10G Switches – 5-Port 10G Switch | TRENDnet - TRENDnet TEG-S750

TRENDnet’s 5-Port 10G Switch, model TEG-S750, provides advanced high bandwidth performance, ease of use, and reliability. The TEG-S750 10G switch features five dedicated 10G ports f...

You can get 2.5 Gbps switches too, but they appear to have much lower internal bandwidth. Since you’re likely to encounter computers that support 10 Gbps in the future because it’s an established standard, it’s probably wiser to just go with 10 Gbps today.

Endpoints

The best way to connect on your Mac remains to get a 10 Gbps or multigig Thunderbolt or PCI adapter, which you connect to a 10 Gbps switch, which uses a 2.5 or 5 Gbps backhaul.

On my Mac, I use an OWC 10/5/2.5 Thunderbolt3 adapter. It works great, and adapts well to 2.5 and 5 Gbps.

https://www.owcdigital.com/products/thunderbolt-3-10g-ethernet-adapter

Thunderbolt 3 10G Ethernet Adapter

Adds up to 10Gb/s Ethernet connectivity to Thunderbolt 3-equipped computers that lack built-in capabilities.

My gaming PC comes with a 2.5 Gbps Ethernet connector on the motherboard, and it works great as well.

The story with USB-based adapters is not as rosy. I’ve tried two USB-C Ethernet adapters: a 2.5 Gbps one, and a 5/2.5 Gbps one, both made by TRENDnet. Neither delivered what they promised.

The problem seems to be that USB 3.1 gets bogged down with overhead very quickly, which is especially problematic when you have a barrage of small packets to be serviced. In practical terms, USB 3.1 Ethernet adapters max out at 1.3 Gbps sustained throughput, regardless of Ethernet cable speed.

tl;dr

In summary, here are my findings if you want to upgrade your home networking to multigig Ethernet:

  • Buy 10/5/2.5 Gbps switches for best performance and compatibility. It’s worth the extra price.
  • Don’t buy 2.5 Gbps switches unless you’re constrained by budget or space.
  • Buy 10/5/2.5 Thunderbolt3 or PCI endpoints.
  • Don’t buy USB 3.1 dongles that claim to be faster than 1 Gbps. They don’t deliver.