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5K iMac Thunderbolt ports
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Good question, I thought it was per port but you might be on to something. Hopefully someone can chime in to explain. I would like to use 2 RAID0 setups on each port to combine them as one.
I think that the System Information window/Thunderbolt will show you how those devices are connected.
If there is more than one bus (with 9 devices, then the device tree will show that.
I expect that you have more buses available, if some or all of your devices are attached through a Thunderbolt dock.
But the internal hardware has only one bus available.
And, the device tree will make that clear.
Does any Mac other than the nMP have more than one TB bus?
If there is more than one bus (with 9 devices, then the device tree will show that.
I expect that you have more buses available, if some or all of your devices are attached through a Thunderbolt dock.
But the internal hardware has only one bus available.
And, the device tree will make that clear.
Does any Mac other than the nMP have more than one TB bus?
I have a pair of 4TB RAID0 that I would like to make into one 8TB RAID0 but it would require them to be on a separate bus to work efficiently/correctly.
Not really, because the bandwidth is more than sufficient to handle 4 hard drives in RAID0. I actually have 4 x 2TB Toshibas in RAID0 inside an OWC Thunderbay IV and BlackMagic benchmarks at around 720MB/sec peak.
Explanation: The THunderbolt2 controller is a Falcon Ridge controller. It connects to the PCIe 2.0 bus using 4-lanes and provides 2 Thunderbolt ports.
For example, the Mac Pro provides 6 Thunderbolt ports, using 3 Falcon Ridge controllers.
When Alpine Ridge Thunderbolt3 controllers come into use, there will still only be 4 PCIe lanes used and 2 Thunderbolt3 ports provided. The increased speed comes from the PCIe 3.0 bus.
More info here for Thunderbolt2:
http://www.anandtech.com/show/7049/intel-thunderbolt-2-everything-you-need-to-know
For example, the Mac Pro provides 6 Thunderbolt ports, using 3 Falcon Ridge controllers.
When Alpine Ridge Thunderbolt3 controllers come into use, there will still only be 4 PCIe lanes used and 2 Thunderbolt3 ports provided. The increased speed comes from the PCIe 3.0 bus.
More info here for Thunderbolt2:
http://www.anandtech.com/show/7049/intel-thunderbolt-2-everything-you-need-to-know
Right, but that's probably in one enclosure. I have 2 enclosures that each have 2 drives (2TB each) to make the 4TB RAID0. I want to access both enclosures as one 8TB RAID0. I don't think daisy chaining the 2 enclosures would work as expected hence the desire for two separate buses.
You'll find on iMac that performance would be same either daisychained or one into each port. With right drives, you could get up to 1.3GB/sec on your iMac.
That's what you can get with one LaCie Little Big Disk, RAID-0, across 2 PCIE SSDs.
Other than "fast", what performance do you really need?
Has little to do with PCIe and all to do with the available channels in the Thunderbolt protocol. Thunderbolt 1 and 2 don't differ that much. The only reason why TB2 is faster is because it is able to aggregate channels. Both TB1 and 2 have 4 channels in total, 2 per port and each channel is able to do 10Gb/s. If you aggregate all the channels of 1 port you get a bandwidth of 20Gb/s (that's why the System Profile screenshot reports "10Gbit/s x2" and "10Gbit/s x1").
In case of TB3 things are quite different as there are a lot of changes. PCIe 3 is one of them and should be the main component that increases the speed.
For those of you wondering, the amount of devices is per port, so max 6 per port. In case of the iMac that means a total of 12 devices (2x6). If you need more ports you need additional controller(s) like the Mac Pro (it uses 3 controllers to provide 6 ports).
In that case your reply is completely offtopic here and only causing confusion. The question is about Thunderbolt ports which are connected to the Thunderbolt controller. How the controller is connected to the rest of the machine and how the rest of the machine interacts with it (and vice versa) doesn't matter in this case. The Thunderbolt ports do not speak any other language than Thunderbolt. It is the controller that will have to speak the other languages (DisplayPort, PCIe and later on USB3.1). The only exception would be Thunderbolt 3 because the newer PCIe version is one of the main reasons why Thunderbolt 3 is faster.
This is about the Thunderbolt side of things. Anything else is offtopic.
This is about the Thunderbolt side of things. Anything else is offtopic.