How to see Thunderbolt Bandwidth usage on 2017 iMac?

[propower]

I am a pro audio guy and am considering hanging a nVme drive off of the TB3 port of my 2017 iMac. I also daisy chain the following from the other TB3 port (which shares the TB3 bandwidth - one TB3 bus 2 ports)

Akitio TB3 to 4 SATA drive bays --> Apple TB3 to TB2 adapter
33' Optical TB2 cable --> OWC TB2 Dock (Mouse and 1080P Monitor) -->
33' Optical TB2 cable --> 2nd OWC TB2 Dock (1080P monitor mouse and TB2 audio interface)
I have been using this chain (without an nVme drive for 2 years with no issues.

What I would like to know is how much of my bandwidth is this chain of components using?

So far I can't find any way to monitor the TB3 port for bit rate. Any one here know of an app to do this??

 

[Chancha]

As far as I know, there is a "6 Thunderbolt device" limit per TB bus. For the iMac 2017 since there is only one shared bus per both TB3 ports, so the same limit applies. Though even after the addition of the NVMe drive you are still on a 5th TB device, with some lower bandwidth USB/displayport devices taking bandwidth off the attached chained controller, so on paper this looks good.

I do not know of a direct way of monitoring a combined or even detailed bandwidth usage over a TB grid. Some eGPU folks who really need to know this would do it from reverse, they use a monitoring tool for the GPU, and observe how much is bandwidth deducted once other TB devices get active.

What will be the role of the NVMe drive? If there is a boot volume it may be taxing. But if it is just for data, even frequently accessed like writing active project files and recorded audio it is probably okay. It seems like your whole setup chain really has no point that would require full bandwidth potential continuously like an eGPU and a 5K display do.