The author upgraded their Mac Studio's 10 Gigabit Ethernet to 25 Gbps using a cost-effective Thunderbolt adapter. While commercial 25 Gbps solutions like Sonnet's Twin25G Adapter ($999) and Atto's Thunder Link ($1,099) are expensive, a workaround using a server-pulled OCP 2 NIC with a Thunderbolt 3 adapter board was found for around $160 (though prices have since increased).

Initial testing revealed two issues: an outdated iperf3 version on the NAS limited speeds, and the NIC enclosure overheated. Compiling the latest iperf3 resolved the speed limitation, reaching up to 20 Gbps due to Thunderbolt 3 constraints. To address the overheating, the author designed and 3D-printed a fan duct, incorporating a Noctua fan and speed controller for active cooling. This brought the operating temperature down significantly.

The final performance achieved around 1.4 GB/sec read and 1 GB/sec write for Samba file copies, a marginal improvement over the built-in 10 GbE. Despite the effort and cost, the author reflects on the value of the upgrade and the resulting blog post.