Upgrading Mac Studio to 25 Gbps Thunderbolt Ethernet with a DIY Cooling Mod
Getting 25 Gbps Thunderbolt Ethernet on My Mac Studio
I upgraded my Mac Studio from 10 Gigabit to 25 Gbps Ethernet using a budget-friendly OCP 2 NIC adapter. After discovering the device overheated dangerously, I designed and 3D printed a custom enclosure with a Noctua fan for active cooling. The final build delivers stable 20 Gbps speeds while remaining silent, proving that a DIY approach can outperform expensive commercial adapters.
It was acting like a little oven.
- ccssowa
I’m in the process of gradually upgrading an in-house video production studio with <10 seats from 10G to 25/100G. There were attempts to do this years ago, and I found some unused Atto 40G Thunderlink adapters and Sonnet’s 25G adapters. The 40G Attos are EOL, and I couldn’t get the Sonnets to work. The SFP jungle/support/information is really maddening.
Atto’s new 100G Thunderlinks work well. I’ve seen speeds of just over 5 gigabytes per second. Atto definitely does a lot of kernel extension wizardry to get macOS to achieve these speeds.
A bit OT: I hope Blackmagic really shakes up the 100G connectivity market, and that Apple realizes their platform is extremely well-suited for IP Video 2110 workflows — if they can ever get networking under control.
- Neywiny
I'm using the sonnet at work. Work paid for it. Yes it's more expensive. I have gotten over 25 gbps bidirectional, but not by much. Maybe 27. A big downside is that it only supports 15W upstream power which I didn't think to check, so since that laptop only has 2 usb-c ports for power input, it's a bit limiting.
The upside, though, was that I plugged it in, got my throughput, and never had to worry ever again. Remember that engineering time is mucho $$. So troubleshooting overheating, divising a solution, manufacturing it, etc, that all eats into the savings.
The $400 dock would be cool though. It seems smaller than the sonnet and fixes my charging problem. Weirdly I didn't think I'd care about not including transceivers but they did actually come in handy, so that is a downside. Might try to get one of these if I need another one in the future.
- randusername
Can't you just put a real PCIe NIC in an eGPU enclosure with a fan? I bet you can solve this problem for like $150 and two craigslist transactions.
- pzmarzly
One of the YouTube comments pointed out the issue is most likely the lack of support for SMB Direct (RDMA) in macOS. Would be nice to repeat the test on a Windows/Linux laptop.
- alsetmusic
Dang, here I was feeling slick with 10Gb between my MBP and Mac mini and NAS. That’s the thing, it could always be bigger / faster / more. It’s enough for my workflow, but it’s fun to see people push further.
- dcrazy
Jeff, I’m curious whether you really would have needed the $1,000 version of the Sonnet TB5 PCIe chassis. Would this $400 one have sufficed? https://www.bhphotovideo.com/c/product/1932655-REG/sonnet_ec...
- GeekyBear
As mentioned in the blog post's footnote, the bottleneck may just be on the NAS side:
> this real-world speed limitation could also be related to my use of my lower-power Arm NAS (running on Ampere Altra, with 32 fairly-slow CPU cores). I was testing writing to an array of fast enterprise NVMe SSDs, so they shouldn't be the bottleneck here.
He was only getting 1 Gigabyte of throughput out of the built in 10 Gigabit Ethernet connection and moving to the 25 Gigabit connection only made a marginal impact on throughput, after all.
- rconti
For us <25Gbps plebes out there: For god's sake do not buy a USB-C RealTek RTL8156-equipped multi-gig ethernet dongle to use with your Mac. I went through 3, and they're all trash:
Plugable 2.5G USB-C to ethernet adapter (bought November 2025), SABRENT USB C to 2.5Gbps ethernet adapter (bought October 2024), UGREEN USB C 2.5G ethernet adapter (also October 2024). In my experience they immediately fall on their face in a speedtest and drop to a couple hundred Mbps, experience packet loss, etc. This is testing across a few modern Apple Silicon Macs.
I now have a WavLink WL-NWU341G 5Gbps dongle with the RTL-8157 that seems to work well, but I've only run a couple of tests-- I am away from my home setup and don't have wired ethernet run to all the rooms where I'm living.
If you do some Googling, there's some good information out there about it, but when I bought the bad ones, I couldn't find any information corroborating my experience.