● Covered by 1 source · 1 reportLow impact1 neutral
Achieving 25 Gbps Thunderbolt Ethernet on Mac Studio with a DIY adapter
Key points
- Mac Studio's built-in Ethernet is 10 Gbps.
- Commercial 25G Thunderbolt adapters are expensive.
- A custom solution uses a server OCP 2 NIC with a Thunderbolt 3 adapter.
- Challenges included old iperf3 version and NIC overheating.
Upgrading Mac Studio Networking
The author sought to upgrade their Mac Studio's network connection from the built-in 10 Gigabit Ethernet to 25 Gigabit Ethernet. The existing 10 Gbps connection was sufficient for tasks like 4K video editing from a NAS and backups at 1 GB/sec, but the user desired higher speeds after upgrading their rack and NAS to 25 GbE.
Costly Commercial Options
Commercial 25G networking options for Mac are expensive, with products like Sonnet's Twin25G Adapter at $999 and Atto's ThunderLink at $1,099. Raiden Digit's LightOne 25GbE Docking Station is priced at $399. Macs require Thunderbolt adapters, as they do not support inexpensive PCIe cards directly.
DIY Adapter Solution
A more affordable solution was found through Christian Kohlschütter's blog post, detailing a cheap 25G Thunderbolt adapter. This adapter utilizes a server-pulled OCP 2 NIC combined with a Thunderbolt 3 adapter board. Initially priced at $160, the Amazon listing later increased to $299.
Initial Testing and Challenges
After installing the new fiber cabling, initial bandwidth tests using iperf3 between the Mac and NAS revealed two issues. The iperf3 version on the NAS was outdated, limiting speeds to 15 Gbps. Additionally, the 25G NIC enclosure became excessively hot, indicating thermal problems.
Resolving Performance and Thermal Issues
The iperf3 issue was resolved by compiling the latest version, which allowed for multi-threading and increased speeds to 20 Gbps. This speed is near the limit for the Thunderbolt 3 chipset. The overheating NIC was identified as a design flaw, as OCP 2 NICs are designed for server environments with active cooling, not passively-cooled enclosures. The enclosure lacked proper thermal bonding to the NIC chips.
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Reporting from
A user successfully configured a 25 Gbps Thunderbolt Ethernet connection on a Mac Studio using a custom adapter solution. This involved addressing software and hardware limitations to achieve higher network speeds than the built-in 10 Gigabit Ethernet.