Thunderbolt bandwidth shared between ports?
 
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xinux
(@xinux)
Active Member
Joined: 10 months ago
 

I have the Aorus RTX 2070 Gaming Box
Because I want to utilize its full potential, I have installed the H2D firmware update to maximize gpu bandwidth. 
I expected to be able to connect a dock to the second thunderbolt port on my X1 Carbon. However, I'm getting connectivity problems with my USB devices. 

Is the thunderbolt bandwidth shared between the two ports? 
If so, would I have better luck using a non-thunderbolt usb-c dock?

2019 14" Lenovo Thinkpad X1 Carbon Gen 7 [8th,4C,U] + RTX 2070 @ 32Gbps-TB3 (AORUS Gaming Box) + Win10 [build link]  

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itsage
(@itsage)
Illustrious Member Admin
Joined: 4 years ago
 

Which Thunderbolt 3 dock are you using for USB devices?

external graphics card builds
best laptops for external GPU
eGPU enclosure buyer's guide

 
2020 13" MacBook Pro [10th,4C,G] + RX 5700 @ 32Gbps-TB3 (Prototype eGPU Enclosure) + macOS 10.15.4 & Win10 1903 [build link]  


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xinux
(@xinux)
Active Member
Joined: 10 months ago
 
Posted by: @itsage

Which Thunderbolt 3 dock are you using for USB devices?

The Thinkpad Thunderbolt Dock Gen 2. 
Here is my build: 
https://egpu.io/forums/builds/2019-14-lenovo-thinkpad-x1-carbon-g7-8th4cu-rtx-207032gbps-tb3-aorus-gaming-box-win10-xinux/

2019 14" Lenovo Thinkpad X1 Carbon Gen 7 [8th,4C,U] + RTX 2070 @ 32Gbps-TB3 (AORUS Gaming Box) + Win10 [build link]  

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DrEGPU
(@dregpu)
Trusted Member
Joined: 2 years ago
 
Posted by: @xinux

Is the thunderbolt bandwidth shared between the two ports? 

Unfortunately, yes. Only the recent Apple Macbook pros have 2x TB3 controllers to allow for 2x 40Gbps. The exception (sort of), are the Alienware line machines from Dell which have both a TB3 port and a dell-specific AGA port, allowing 2 eGPUs (one being the Dell graphics amplifier) OR the AGA plus a TB3 dock.

MBP 2018 16 inch + Razer Core X@40Gbps-TB1 (Zotac RTX 2080 Ti Amp) + Ubuntu 20.04, Win10

 
2011 13" MacBook Pro [2nd,2C,M] + RTX 2080 Ti @ 10Gbps-TB1>TB3 (Razer Core X) + Linux Ubuntu 18.04.02 LTS [build link]  


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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

A lack of bandwidth shouldn't cause a USB device to loose power like you describe in your build post.

The Thinkpad Thunderbolt Dock Gen 2 appears to be a Titan Ridge based dock so it can work with both Thunderbolt 3 and USB-C computers. You don't have a USB-C only port, so you can't force it to work in USB-C mode. I don't know if a USB-C dock would help.

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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xinux
(@xinux)
Active Member
Joined: 10 months ago
 
Posted by: @dregpu
Posted by: @xinux

Is the thunderbolt bandwidth shared between the two ports? 

Unfortunately, yes. Only the recent Apple Macbook pros have 2x TB3 controllers to allow for 2x 40Gbps. The exception (sort of), are the Alienware line machines from Dell which have both a TB3 port and a dell-specific AGA port, allowing 2 eGPUs (one being the Dell graphics amplifier) OR the AGA plus a TB3 dock.

That's too bad.. guess I should have done my homework.

Posted by: @joevt

A lack of bandwidth shouldn't cause a USB device to loose power like you describe in your build post.

The Thinkpad Thunderbolt Dock Gen 2 appears to be a Titan Ridge based dock so it can work with both Thunderbolt 3 and USB-C computers. You don't have a USB-C only port, so you can't force it to work in USB-C mode. I don't know if a USB-C dock would help.

I'm not sure it loses power, but my devices stop working for a brief moment. My keyboard backlight flashes, and my mouse stops moving for a second. I'm pretty sure it's the same symptom you get when you connect the devices directly to the Gaming Box
I guess I'll have to look at usb-a docks. 

2019 14" Lenovo Thinkpad X1 Carbon Gen 7 [8th,4C,U] + RTX 2070 @ 32Gbps-TB3 (AORUS Gaming Box) + Win10 [build link]  

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joevt
(@joevt)
Noble Member
Joined: 3 years ago
 

There's some weird USB behavior mentioned in another post. Can this problem be similar?
https://egpu.io/forums/gpu-monitor-peripherals/egpu-usb-device-issues/

Mac mini (2018), Mac Pro (Early 2008), MacBook Pro (Retina, 15-inch, Mid 2015), GA-Z170X-Gaming 7, Sapphire Pulse Radeon RX 580 8GB GDDR5, Sonnet Echo Express III-D, Trebleet Thunderbolt 3 to NVMe M.2 case


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xinux
(@xinux)
Active Member
Joined: 10 months ago
 
Posted by: @joevt

There's some weird USB behavior mentioned in another post. Can this problem be similar?
https://egpu.io/forums/gpu-monitor-peripherals/egpu-usb-device-issues/

This seems relevant, thanks. Maybe it isn't a bandwidth problem. 
At the very least it's not limited to thunderbolt; I just tried with an USB-A hub and it's having the same problems.

2019 14" Lenovo Thinkpad X1 Carbon Gen 7 [8th,4C,U] + RTX 2070 @ 32Gbps-TB3 (AORUS Gaming Box) + Win10 [build link]  

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