Jeff Geerling documents his experience adding 25 Gbps Ethernet to a Mac Studio via a cheap OCP 2 NIC with a Thunderbolt 3 adapter board. The adapter cost around $160-$299 compared to $999+ commercial options. Two main challenges arose: an outdated iperf3 on the NAS capping speeds at 15 Gbps (fixed by recompiling), and severe overheating of the passively-cooled enclosure. The thermal fix involved designing and 3D-printing a custom fan duct in Noctua-branded PLA, mounting an 80mm Noctua 5V fan, and soldering power directly from the PCB. Final temperatures dropped below 36°C. Real-world Samba transfer speeds reached ~1.4 GB/s read and ~1 GB/s write — only a modest improvement over the built-in 10G Ethernet, raising questions about whether the effort was worthwhile.
