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AppleInsider Mac mini review

A 2018 MBP15" has two TB3 controllers for four ports.

Unless it's a secret, Intel don't make a 4-port TB3 controller that I'm aware of - it's either PCIe 3.0 ×4 for 2 ports (aka Double Port), PCIe 3.0 ×4 for 1 port (aka Single Port) or PCIe 3.0 ×2 for one port (aka Low Power)
 
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Stephen.R said:
A 2018 MBP15" has two TB3 controllers for four ports.

Unless it's a secret, Intel don't make a 4-port TB3 controller that I'm aware of - it's either PCIe 3.0 ×4 for 2 ports (aka Double Port), PCIe 3.0 ×4 for 1 port (aka Single Port) or PCIe 3.0 ×2 for one port (aka Low Power)
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One controller gives full speed on two ports, right?
 
StellarVixen said:
Go to the fourth page of comments. The reviewer says there is one TB3 controller for ALL FOUR Thunderbolt™ 3 ports.

So I guess I can forget about getting full 40 Gbps from both graphics card and external NVMe drive, for example.
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Did you read further through that particular thread? A few additional comments from Mike:


It appears to be one controller, with two buses. Titan Ridge is over-provisioned from a bandwidth standpoint versus Alpine Ridge and expressly allows for this. but you're right this would be a problem with the older controller.

We'll be torturing the TB3 subsystem a bit later in the week and next week, but so far, we're not seeing any issues with the high-speed SSD in the red enclosure you see in the pic which can shove data very nearly at 40gbit/sec, in conjunction with the Apple Thunderbolt display. We'll push it to the max with multiple displays and drives.
Click to expand...

... and in response to, "Marco Arment just tweeted that there are two TB3 controllers. Can you look in the hardware profile? It should be there."

The profiler shows buses, not controllers, doesn't have to be a a 1:1 correlation with Titan Ridge. Titan Ridge can do two buses per controller, plus Apple has explicitly told us that there is one controller for the two buses. We've been given wrong info by Apple before, though, which is why we're relaying what Apple has said, and also waiting for the teardown. Trust but verify.

GPUs aren't constantly using all 32gbit/sec, even with multiple 4K displays hanging off the box. In most cases, even if limited to 40gbit/sec by the controller -- which Titan Ridge is not -- the user will see no speed issues with that setup you're describing.
Click to expand...
 
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D.T. said:
Did you read further through that particular thread? A few additional comments from Mike:




... and in response to, "Marco Arment just tweeted that there are two TB3 controllers. Can you look in the hardware profile? It should be there."
Click to expand...
I must admit that I do not understand a single damn thing from this. Does this mean 40Gbps on all four ports or not?
 
I think it means "It's 40Gbps on all four ports together, but it's not a big problem in practice".

Of course, that only covers the "wall of displays" use case only.
It would be equally interesting to know, if the 10GB NIC is somehow sharing the bus with the TB3 controller(s).
 
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