The new Mac Pros out there can really pack a punch and throughput data is at faster rates than ever, but there’s still a few limitations that need to be considered to get your setup working as smoothly and efficiently as possible. This really becomes more relevant if you’re plugging in a lot of high bandwidth devices such as raid arrays, PCIe expansion chassis, etc.
If we keep in mind the Mac Pro Thunderbolt bus setup below, we can easily balance the load, giving the most IO to your most important devices:
As a general rule, never share your storage and video IO devices with your GUI monitors some of the newer (high resolution) monitors can take an unexpected amount of the available bandwidth.
Other rules to keep in mind are to group (and/or daisy-chain) low bandwidth devices on a single bus, or even use the USB3 ports if the device allows.
A case in point – while visiting a friend in Melbourne recently, they mentioned an issue where playing back 4K material out of their DaVinci Resolve with Blackmagic IO they were experiencing line dropouts on the SDI monitor. Although the issue appeared sporadic, it was affecting the operators and their ability to perform seamless playback in client sessions.
A quick look at the system showed their Blackmagic IO was sharing a bus with the 1st GUI monitor, and their Pegasus storage was sharing a bus with the 2nd GUI monitor. The rarely used fibre connection back to the SAN was on its own bus, and hardly used.
To get things singing again, we decided to dedicate as much bandwidth possible to the Pegasus and Blackmagic devices by putting each of them on their own bus, and then chain the monitors off each other, sharing the same bus as the rarely used Fibre Storage.
As soon as we made this configuration change, playback was perfect.
If these rules are kept in mind, you should be able to balance your system with relative ease, and get the most from your peripheral devices.