[JIM] Thunderbolt PCIe Speed Limitations v.2026.x
As Apple moves away from the Mac Pro, ToolsOnAir validates Thunderbolt-based hardware configurations for reliable multi-channel recording.
With the discontinuation of the Mac Pro, professional video recording workflows on macOS are entering a new phase. For many broadcasters, production companies, universities, houses of worship, corporate studios, and live event teams, the question is no longer only which Mac to use, but how to build a reliable recording system around Thunderbolt, PCIe video cards, and external expansion chassis.
This is especially important for all just:in mac pro and Just In Mac Lite customers. Both products are designed for professional multi-channel recording, but the final system performance always depends on the complete hardware chain: the Mac, the Thunderbolt connection, the expansion chassis, the video I/O card, the video format, and the selected recording parameters.
Thunderbolt 3 provides an aggregate bandwidth of approximately 2750 MB/s when considering overhead and shared system resources. However, when working with uncompressed video data, several factors such as resolution, colour depth, pixel format, and frame rate play a crucial role in determining the actual bandwidth requirements. For example, a 1080p video signal at 60 fps with 10-bit colour depth in YUV 4:2:2 format typically requires around 248.8 MB/s.
We have also extended our testing to Thunderbolt 5-based setups. While Thunderbolt 5 provides significantly more overall bandwidth compared to Thunderbolt 3, the achievable channel count still depends on many factors, including the PCIe implementation of the expansion chassis, the video I/O card, the codec, the storage performance, and the overall system configuration. In particular, it is important to understand that many AJA and Blackmagic Design video cards are still PCIe 3.0 cards and not PCIe 4.0 cards. In addition, many Thunderbolt expansion chassis still provide a four-lane PCIe connection to the installed card. This means that even with Thunderbolt 5, the video card may still be limited by PCIe lane count and PCIe generation.
Because of these variables, precise calculations are challenging and real-world testing is essential. Based on our Thunderbolt 3 and Thunderbolt 5 tests, we recommend the hardware setups listed above, as they have been tested and verified by ToolsOnAir for reliable multichannel capture workflows. These recommendations are especially important for customers planning high-channel-count systems with Mac mini, Mac Studio, or other Thunderbolt-based systems.
For best results, we generally recommend distributing capture channels across different Thunderbolt ports whenever possible and contacting us when planning multichannel recording systems.
ToolsOnAir will be happy to help evaluate the right combination of Mac, Thunderbolt expansion chassis, video I/O card, storage, and recording codec to achieve the required channel count reliably.